Added documentation for wxDbTable class

[wxWidgets.git] / docs / latex / wx / db.tex

\section{\class{wxDb}}\label{wxdb}

A wxDb instance is a connection to an ODBC data source which may
be opened, closed, and re-opened an unlimited number of times.  A
database connection allows function to be performed directly on the
data source, as well as allowing access to any tables/views defined in
the data source to which the user has sufficient privileges.

\wxheading{Include files}

<wx/db.h>

\wxheading{Helper classes and data structures}

The following classes and structs are defined in db.cpp/.h for use with the wxDb class.

\begin{itemize}\itemsep=0pt
\item \helpref{wxDbColFor}{wxdbcolfor}
\item \helpref{wxDbColInf}{wxdbcolinf}
\item \helpref{wxDbTableInf}{wxdbtableinf}
\item \helpref{wxDbInf}{wxdbinf}
\end{itemize}

\wxheading{Constants}

NOTE: In a future release, all ODBC class constants will be prefaced with 'wx'

\begin{verbatim}

    wxDB_PATH_MAX           Maximum path length allowed to be passed to the ODBC
                            driver to indicate where the data file is located.

    DB_MAX_COLUMN_NAME_LEN  Maximum supported length for the name of a column

    DB_MAX_ERROR_HISTORY    Maximum number of error messages retained in the
                            queue before being overwritten by new errors.

    DB_MAX_ERROR_MSG_LEN    Maximum supported length of an error message returned 
                            by the ODBC classes

    DB_MAX_STATEMENT_LEN    Maximum supported length for a complete SQL statement
                            to be passed to the ODBC driver

    DB_MAX_TABLE_NAME_LEN   Maximum supported length for the name of a table

    DB_MAX_WHERE_CLAUSE_LEN Maximum supported WHERE clause length that can be 
                            passed to the ODBC driver

    DB_TYPE_NAME_LEN        Maximum length of the name of a column's data type
\end{verbatim}


\wxheading{Enumerated types}

\docparam{enum {\bf wxDbSqlLogState}}{sqlLogOFF, sqlLogON}

{\it enum {\bf wxDBMS}}

These are the databases currently tested and working with the ODBC classes.  A call to \helpref{wxDb::Dbms}{wxdbdbms} will return one of these enumerated values listed below.

\begin{verbatim}
      dbmsUNIDENTIFIED
      dbmsORACLE
      dbmsSYBASE_ASA     // Adaptive Server Anywhere
      dbmsSYBASE_ASE     // Adaptive Server Enterprise
      dbmsMS_SQL_SERVER
      dbmsMY_SQL
      dbmsPOSTGRES
      dbmsACCESS
      dbmsDBASE
      dbmsINFORMIX
      dbmsVIRTUOSO
      dbmsDB2
\end{verbatim}

See the remarks in \helpref{wxDb::Dbms}{wxdbdbms} for exceptions/issues with each of these database engines.

\wxheading{Public member variables}

\docparam{SWORD {\bf wxDb::cbErrorMsg}}{This member variable is populated as a result of calling \helpref{wxDb::GetNextError}{wxdbgetnexterror}.  Contains the count of bytes in the wxDb::errorMsg string.}

\docparam{int {\bf wxDb::DB\_STATUS}}{The last ODBC error that occurred on this data connection.  Possible codes are:}

\begin{verbatim}
   DB_ERR_GENERAL_WARNING                     // SqlState = '01000'
   DB_ERR_DISCONNECT_ERROR                    // SqlState = '01002'
   DB_ERR_DATA_TRUNCATED                      // SqlState = '01004'
   DB_ERR_PRIV_NOT_REVOKED                    // SqlState = '01006'
   DB_ERR_INVALID_CONN_STR_ATTR               // SqlState = '01S00'
   DB_ERR_ERROR_IN_ROW                        // SqlState = '01S01'
   DB_ERR_OPTION_VALUE_CHANGED                // SqlState = '01S02'
   DB_ERR_NO_ROWS_UPD_OR_DEL                  // SqlState = '01S03'
   DB_ERR_MULTI_ROWS_UPD_OR_DEL               // SqlState = '01S04'
   DB_ERR_WRONG_NO_OF_PARAMS                  // SqlState = '07001'
   DB_ERR_DATA_TYPE_ATTR_VIOL                 // SqlState = '07006'
   DB_ERR_UNABLE_TO_CONNECT                   // SqlState = '08001'
   DB_ERR_CONNECTION_IN_USE                   // SqlState = '08002'
   DB_ERR_CONNECTION_NOT_OPEN                 // SqlState = '08003'
   DB_ERR_REJECTED_CONNECTION                 // SqlState = '08004'
   DB_ERR_CONN_FAIL_IN_TRANS                  // SqlState = '08007'
   DB_ERR_COMM_LINK_FAILURE                   // SqlState = '08S01'
   DB_ERR_INSERT_VALUE_LIST_MISMATCH          // SqlState = '21S01'
   DB_ERR_DERIVED_TABLE_MISMATCH              // SqlState = '21S02'
   DB_ERR_STRING_RIGHT_TRUNC                  // SqlState = '22001'
   DB_ERR_NUMERIC_VALUE_OUT_OF_RNG            // SqlState = '22003'
   DB_ERR_ERROR_IN_ASSIGNMENT                 // SqlState = '22005'
   DB_ERR_DATETIME_FLD_OVERFLOW               // SqlState = '22008'
   DB_ERR_DIVIDE_BY_ZERO                      // SqlState = '22012'
   DB_ERR_STR_DATA_LENGTH_MISMATCH            // SqlState = '22026'
   DB_ERR_INTEGRITY_CONSTRAINT_VIOL           // SqlState = '23000'
   DB_ERR_INVALID_CURSOR_STATE                // SqlState = '24000'
   DB_ERR_INVALID_TRANS_STATE                 // SqlState = '25000'
   DB_ERR_INVALID_AUTH_SPEC                   // SqlState = '28000'
   DB_ERR_INVALID_CURSOR_NAME                 // SqlState = '34000'
   DB_ERR_SYNTAX_ERROR_OR_ACCESS_VIOL         // SqlState = '37000'
   DB_ERR_DUPLICATE_CURSOR_NAME               // SqlState = '3C000'
   DB_ERR_SERIALIZATION_FAILURE               // SqlState = '40001'
   DB_ERR_SYNTAX_ERROR_OR_ACCESS_VIOL2        // SqlState = '42000'
   DB_ERR_OPERATION_ABORTED                   // SqlState = '70100'
   DB_ERR_UNSUPPORTED_FUNCTION                // SqlState = 'IM001'
   DB_ERR_NO_DATA_SOURCE                      // SqlState = 'IM002'
   DB_ERR_DRIVER_LOAD_ERROR                   // SqlState = 'IM003'
   DB_ERR_SQLALLOCENV_FAILED                  // SqlState = 'IM004'
   DB_ERR_SQLALLOCCONNECT_FAILED              // SqlState = 'IM005'
   DB_ERR_SQLSETCONNECTOPTION_FAILED          // SqlState = 'IM006'
   DB_ERR_NO_DATA_SOURCE_DLG_PROHIB           // SqlState = 'IM007'
   DB_ERR_DIALOG_FAILED                       // SqlState = 'IM008'
   DB_ERR_UNABLE_TO_LOAD_TRANSLATION_DLL      // SqlState = 'IM009'
   DB_ERR_DATA_SOURCE_NAME_TOO_LONG           // SqlState = 'IM010'
   DB_ERR_DRIVER_NAME_TOO_LONG                // SqlState = 'IM011'
   DB_ERR_DRIVER_KEYWORD_SYNTAX_ERROR         // SqlState = 'IM012'
   DB_ERR_TRACE_FILE_ERROR                    // SqlState = 'IM013'
   DB_ERR_TABLE_OR_VIEW_ALREADY_EXISTS        // SqlState = 'S0001'
   DB_ERR_TABLE_NOT_FOUND                     // SqlState = 'S0002'
   DB_ERR_INDEX_ALREADY_EXISTS                // SqlState = 'S0011'
   DB_ERR_INDEX_NOT_FOUND                     // SqlState = 'S0012'
   DB_ERR_COLUMN_ALREADY_EXISTS               // SqlState = 'S0021'
   DB_ERR_COLUMN_NOT_FOUND                    // SqlState = 'S0022'
   DB_ERR_NO_DEFAULT_FOR_COLUMN               // SqlState = 'S0023'
   DB_ERR_GENERAL_ERROR                       // SqlState = 'S1000'
   DB_ERR_MEMORY_ALLOCATION_FAILURE           // SqlState = 'S1001'
   DB_ERR_INVALID_COLUMN_NUMBER               // SqlState = 'S1002'
   DB_ERR_PROGRAM_TYPE_OUT_OF_RANGE           // SqlState = 'S1003'
   DB_ERR_SQL_DATA_TYPE_OUT_OF_RANGE          // SqlState = 'S1004'
   DB_ERR_OPERATION_CANCELLED                 // SqlState = 'S1008'
   DB_ERR_INVALID_ARGUMENT_VALUE              // SqlState = 'S1009'
   DB_ERR_FUNCTION_SEQUENCE_ERROR             // SqlState = 'S1010'
   DB_ERR_OPERATION_INVALID_AT_THIS_TIME      // SqlState = 'S1011'
   DB_ERR_INVALID_TRANS_OPERATION_CODE        // SqlState = 'S1012'
   DB_ERR_NO_CURSOR_NAME_AVAIL                // SqlState = 'S1015'
   DB_ERR_INVALID_STR_OR_BUF_LEN              // SqlState = 'S1090'
   DB_ERR_DESCRIPTOR_TYPE_OUT_OF_RANGE        // SqlState = 'S1091'
   DB_ERR_OPTION_TYPE_OUT_OF_RANGE            // SqlState = 'S1092'
   DB_ERR_INVALID_PARAM_NO                    // SqlState = 'S1093'
   DB_ERR_INVALID_SCALE_VALUE                 // SqlState = 'S1094'
   DB_ERR_FUNCTION_TYPE_OUT_OF_RANGE          // SqlState = 'S1095'
   DB_ERR_INF_TYPE_OUT_OF_RANGE               // SqlState = 'S1096'
   DB_ERR_COLUMN_TYPE_OUT_OF_RANGE            // SqlState = 'S1097'
   DB_ERR_SCOPE_TYPE_OUT_OF_RANGE             // SqlState = 'S1098'
   DB_ERR_NULLABLE_TYPE_OUT_OF_RANGE          // SqlState = 'S1099'
   DB_ERR_UNIQUENESS_OPTION_TYPE_OUT_OF_RANGE // SqlState = 'S1100'
   DB_ERR_ACCURACY_OPTION_TYPE_OUT_OF_RANGE   // SqlState = 'S1101'
   DB_ERR_DIRECTION_OPTION_OUT_OF_RANGE       // SqlState = 'S1103'
   DB_ERR_INVALID_PRECISION_VALUE             // SqlState = 'S1104'
   DB_ERR_INVALID_PARAM_TYPE                  // SqlState = 'S1105'
   DB_ERR_FETCH_TYPE_OUT_OF_RANGE             // SqlState = 'S1106'
   DB_ERR_ROW_VALUE_OUT_OF_RANGE              // SqlState = 'S1107'
   DB_ERR_CONCURRENCY_OPTION_OUT_OF_RANGE     // SqlState = 'S1108'
   DB_ERR_INVALID_CURSOR_POSITION             // SqlState = 'S1109'
   DB_ERR_INVALID_DRIVER_COMPLETION           // SqlState = 'S1110'
   DB_ERR_INVALID_BOOKMARK_VALUE              // SqlState = 'S1111'
   DB_ERR_DRIVER_NOT_CAPABLE                  // SqlState = 'S1C00'
   DB_ERR_TIMEOUT_EXPIRED                     // SqlState = 'S1T00'
\end{verbatim}

\docparam{struct {\bf wxDb::dbInf}}{This structure is internal to the wxDb class and contains details of the ODBC datasource that the current instance of the wxDb is connected to in its members.  When the data source is opened, all of the information contained in the dbInf structure is queried from the data source.  This information is used almost exclusively within the ODBC class library.  Where there is a need for this information outside of the class library a member function such as wxDbTable::IsCursorClosedOnCommit() has been added for ease of use.}

\begin{verbatim}
   char   dbmsName[40]        - Name of the dbms product
   char   dbmsVer[64]         - Version # of the dbms product
   char   driverName[40]      - Driver name
   char   odbcVer[60]         - ODBC version of the driver
   char   drvMgrOdbcVer[60]   - ODBC version of the driver manager
   char   driverVer[60]       - Driver version
   char   serverName[80]      - Server Name, typically a connect string
   char   databaseName[128]   - Database filename
   char   outerJoins[2]       - Does datasource support outer joins
   char   procedureSupport[2] - Does datasource support stored procedures
   UWORD  maxConnections      - Maximum # of connections datasource supports
   UWORD  maxStmts            - Maximum # of HSTMTs per HDBC
   UWORD  apiConfLvl          - ODBC API conformance level
   UWORD  cliConfLvl          - Is datasource SAG compliant
   UWORD  sqlConfLvl          - SQL conformance level
   UWORD  cursorCommitBehavior   - How cursors are affected on db commit
   UWORD  cursorRollbackBehavior - How cursors are affected on db rollback
   UWORD  supportNotNullClause   - Does datasource support NOT NULL clause
   char   supportIEF[2]       - Integrity Enhancement Facility (Ref. Integrity)
   UDWORD txnIsolation        - Transaction isolation level supported by driver
   UDWORD txnIsolationOptions - Transaction isolation level options available
   UDWORD fetchDirections     - Fetch directions supported
   UDWORD lockTypes           - Lock types supported in SQLSetPos
   UDWORD posOperations       - Position operations supported in SQLSetPos
   UDWORD posStmts            - Position statements supported
   UDWORD scrollConcurrency   - Scrollable cursor concurrency options supported
   UDWORD scrollOptions       - Scrollable cursor options supported
   UDWORD staticSensitivity   - Can additions/deletions/updates be detected
   UWORD  txnCapable          - Indicates if datasource supports transactions
   UDWORD loginTimeout        - Number seconds to wait for a login request
\end{verbatim}

\docparam{char {\bf wxDb::errorList}[DB_MAX_ERROR_HISTORY][DB_MAX_ERROR_MSG_LEN]}{The last n ODBC errors that have occurred on this database connection.}

\docparam{char {\bf wxDb::errorMsg}[SQL_MAX_MESSAGE_LENGTH]}{This member variable is populated as a result of calling \helpref{wxDb::GetNextError}{wxdbgetnexterror}.  It contains the ODBC error message text.}

\docparam{SDWORD {\bf wxDb::nativeError}}{Set by wxDb::DispAllErrors, wxDb::GetNextError, and wxDb::DispNextError.  It contains the datasource-specific error code returned by the datasource to the ODBC driver.  Used for reporting ODBC errors.}

\docparam{wxChar {\bf wxDb::sqlState}[20]}{Set by wxDb::TranslateSqlState().  Indicates the error state after a failed ODBC operation.  Used for reporting ODBC errors.}

\wxheading{Remarks}

Default cursor scrolling is defined by wxODBC_FWD_ONLY_CURSORS in setup.h
when the wxWindows library is built.  This behavior can be overridden when 
an instance of a wxDb is created (see \helpref{wxDb constructor}{wxdbconstr}).

\wxheading{See also}

\helpref{wxDbColFor}{wxdbcolfor}, \helpref{wxDbColInf}{wxdbcolinf}, \helpref{wxDbTable}{wxdbtable}, \helpref{wxDbTableInf}{wxdbtableinf}, \helpref{wxDbInf}{wxdbinf}

\subsection{Associated non-class functions}\label{wxdbfunctions}

The following functions are used in conjunction with the wxDb class.

\func{wxDb *}{wxDbGetConnection}{\param{wxDbConnectInf *}{pDbConfig}, \param{bool }{FwdOnlyCursors=(bool)wxODBC_FWD_ONLY_CURSORS}}

\func{bool}{wxDbFreeConnection}{\param{wxDb *}{pDb}}

\func{void}{wxDbCloseConnections}{\void}

\func{int}{wxDbConnectionsInUse}{\void}

\func{bool}{wxDbSqlLog}{\param{wxDbSqlLogState }{state}, \param{const wxChar *}{filename = SQL_LOG_FILENAME}}

\func{bool}{wxDbGetDataSource}{\param{HENV }{henv}, \param{char *}{Dsn}, \param{SWORD }{DsnMax}, \param{char *}{DsDesc}, \param{SWORD }{DsDescMax}, \param{UWORD }{direction = SQL_FETCH_NEXT}}

\latexignore{\rtfignore{\wxheading{Members}}}

\membersection{wxDb::wxDb}\label{wxdbconstr}

\func{}{wxDb}{\void}

Default constructor.

\func{}{wxDb}{\param{HENV &}{aHenv}, \param{bool }{FwdOnlyCursors=(bool)wxODBC_FWD_ONLY_CURSORS}}

Constructor, used to create an ODBC connection to a data source.

\wxheading{Parameters}

\docparam{aHenv}{Environment handle used for this connection.}

\docparam{FwdOnlyCursors}{Will cursors created for use with this datasource connection only allow forward scrolling cursors.}

\wxheading{Remarks}

This is the constructor for the wxDb class.  The wxDb object must
be created and opened before any database activity can occur.

\wxheading{Example}

\begin{verbatim}
   wxDbConnectInf ConnectInf;
   ....Set values for member variables of ConnectInf here

   wxDb sampleDB(ConnectInf.Henv);
   if (!sampleDB.Open(ConnectInf.Dsn, ConnectInf.Uid, ConnectInf.AuthStr))
   {
      // Error opening data source
   }
\end{verbatim}


\membersection{wxDb::Catalog}\label{wxdbcatalog}

\func{bool}{Catalog}{\param{char *}{ userID}, \param{char *}{fileName = SQL_CATALOG_FILENAME}}

Allows a data "dictionary" of the data source to be created, dumping pertinent information about all data tables to which the user specified in userID has access. 

\wxheading{Parameters}

\docparam{userID}{Database user name to use in accessing the database.  All tables to which this user has rights will be evaluated in the catalog.}

\docparam{fileName}{{\it OPTIONAL}.  Name of the text file to create and write the DB catalog to.}

\wxheading{Return value}

Returns TRUE if the catalog request was successful, of FALSE if there was some reason the catalog could not be generated

\wxheading{Example}

\begin{verbatim}
============== ============== ================ ========= =======
TABLE NAME     COLUMN NAME    DATA TYPE        PRECISION  LENGTH
============== ============== ================ ========= =======
EMPLOYEE       RECID          (0008)NUMBER            15       8
EMPLOYEE       USER_ID        (0012)VARCHAR2          13      13
EMPLOYEE       FULL_NAME      (0012)VARCHAR2          26      26
EMPLOYEE       PASSWORD       (0012)VARCHAR2          26      26
EMPLOYEE       START_DATE     (0011)DATE              19      16
\end{verbatim}


\membersection{wxDb::Close}\label{wxdbclose}

\func{void}{Close}{\void}

Closes the database connection.

\wxheading{Remarks}

At the end of your program, when you have finished all of your database work, you must close the ODBC connection to the data source.  There are actually four steps involved in doing this as illustrated in the example.  

Any wxDbTable instances which use this connection must be deleted before closing the database connection.

\wxheading{Example}

\begin{verbatim}
   // Commit any open transactions on the data source
   sampleDB.CommitTrans();

   // Delete any remaining wxDbTable objects allocated with new
   delete parts;

   // Close the wxDb connection when finished with it
   sampleDB.Close();

   // Free Environment Handle that ODBC uses
   if (SQLFreeEnv(Db.Henv) != SQL_SUCCESS)
   {
      // Error freeing environment handle
   }
\end{verbatim}


\membersection{wxDb::CommitTrans}\label{wxdbcommittrans}

\func{bool}{CommitTrans}{\void}

Permanently "commits" changes (insertions/deletions/updates) to the database.  

\wxheading{Return value}

Returns TRUE if the commit was successful, or FALSE if the commit failed.

\wxheading{Remarks}

Transactions begin implicitly as soon as you make a change to the database.  At any time thereafter, you can save your work to the database ("Commit") or roll back all of your changes  ("Rollback").  Calling this member function commits all open transactions on this ODBC connection.

\wxheading{Special Note : {\it Cursors} }

\normalbox{It is important to understand that different database/ODBC driver combinations handle
transactions differently.  One thing in particular that you must pay attention to is
cursors, in regard to transactions.  Cursors are what allow you to scroll through
records forward and backward and to manipulate records as you scroll through them.
When you issue a query, a cursor is created behind the scenes.  The cursor keeps track
of the query and keeps track of the current record pointer.  After you commit or
rollback a transaction, the cursor may be closed automatically.  This means you must
requery the data source before you can perform any additional work against the wxDbTable
object.  This is only necessary however if the data source closes the cursor after a
commit or rollback.  Use the wxDbTable::IsCursorClosedOnCommit() member function to
determine the data source's transaction behavior.  Note, it would be very inefficient
to just assume the data source closes the cursor and always requery.  This could put
a significant, unnecessary load on data sources that leave the cursors open after a
transaction.}


\membersection{wxDb::CreateView}\label{wxdbcreateviews}

\func{bool}{CreateView}{\param{char *}{ viewName}, \param{char *}{ colList}, \param{char *}{pSqlStmt}}

Creates a SQL VIEW.  

\wxheading{Parameters}

\docparam{viewName}{The name of the view.  e.g. PARTS_V}

\docparam{colList}{{\it OPTIONAL} Pass in a comma delimited list of column names if you wish to explicitly name each column in the result set.  If not desired, pass in an empty string.}

\docparam{pSqlStmt}{Pointer to the select statement portion of the CREATE VIEW statement.  Must be a complete, valid SQL SELECT statement.}

\wxheading{Remarks}

A 'view' is a logical table that derives columns from one or more other tables or views.  Once the view is created, it can be queried exactly like any other table in the database.

NOTE: Views are not available with all datasources.  Oracle is one example of a datasouce which does support views.

\wxheading{Example}

\begin{verbatim}
   // Incomplete code sample
   db.CreateView("PARTS_SD1", "PN, PD, QTY",  
                 "SELECT PART_NO, PART_DESC, QTY_ON_HAND * 1.1 FROM PARTS \
                  WHERE STORAGE_DEVICE = 1");

   // PARTS_SD1 can now be queried just as if it were a data table.
   // e.g. SELECT PN, PD, QTY FROM PARTS_SD1
\end{verbatim}


\membersection{wxDb::Dbms}\label{wxdbdbms}

\func{wxDBMS }{Dbms}{\void}

\wxheading{Remarks}

The return value will be of the enumerated type wxDBMS.  This enumerated
type contains a list of all the currently tested and supported databases.

Additional databases may be work with these classes, but these databases
returned by this function have been tested and confirmed to work with 
these ODBC classes.

enum wxDBMS includes:

\begin{verbatim}
      dbmsUNIDENTIFIED
      dbmsORACLE
      dbmsSYBASE_ASA
      dbmsSYBASE_ASE
      dbmsMY_SQL_SERVER
      dbmsMY_SQL
      dbmsPOSTGRES
      dbmsACCESS
      dbmsDBASE
      dbmsINFORMIX  
\end{verbatim}

There are known issues with conformance to the ODBC standards with several
datasources listed above.  Please see the overview for specific details on
which datasource have which issues.

\wxheading{Return value}

The return value will indicate which of the supported datasources is 
currently connected to by this connection.  In the event that the
datasource is not recognized, a value of 'dbmsUNIDENTIFIED' is returned.


\membersection{wxDb::DispAllErrors}\label{wxdbdispallerrors}

\func{bool}{DispAllErrors}{\param{HENV}{ aHenv}, {\param}{HDBC}{ aHdbc = SQL_NULL_HDBC}, {\param}{HSTMT}{ aHstmt = SQL_NULL_HSTMT}}

Logs all database errors that occurred as a result of the last executed 
database command.  This logging also includes debug logging when compiled in 
debug mode via \helpref{wxLogDebug}{wxlogdebug}.  If logging is turned on 
via \helpref{wxDb::SetSqlLogging}{wxdbsetsqllogging}, then an entry is also 
logged to the defined log file.

\wxheading{Parameters}

\docparam{aHenv}{A handle to the ODBC environment.}

\docparam{aHdbc}{A handle to the ODBC connection.  Pass this in if the ODBC function call that erred out required a hdbc or hstmt argument.}

\docparam{AHstmt}{A handle to the ODBC statement being executed against.  Pass this in if the ODBC function call  that erred out required a hstmt argument.}

\wxheading{Remarks}

This member function will display all of the ODBC error messages for the last ODBC function call that was made.  Normally used internally within the ODBC class library.  Would be used externally if calling ODBC functions directly (i.e. SQLFreeEnv()).

\wxheading{See also}

\helpref{wxDb::SetSqlLogging}{wxdbsetsqllogging}, wxDbSqlLog

\wxheading{Example}

\begin{verbatim}
   if (SQLExecDirect(hstmt, (UCHAR FAR *) pSqlStmt, SQL_NTS) != SQL_SUCCESS)
      // Display all ODBC errors for this stmt
      return(db.DispAllErrors(db.henv, db.hdbc, hstmt));
\end{verbatim}


\membersection{wxDb::DispNextError}\label{wxdbdispnexterror}

\func{void}{DispNextError}{\void}

\wxheading{Remarks}

This function is normally used internally within the ODBC class library.
It could be used externally if calling ODBC functions directly.  This
function works in conjunction with \helpref{wxDb::GetNextError}{wxdbgetnexterror} when errors (or
sometimes informational messages)  returned from ODBC need to be analyzed
rather than simply displaying them as an error.  GetNextError() retrieves
the next ODBC error from the ODBC error queue.  The wxDb member variables
"sqlState", "nativeError" and "errorMsg" could then be evaluated.  To
display the error retrieved, DispNextError() could then be called.
The combination of GetNextError() and DispNextError() can be used to
iteratively step through the errors returned from ODBC evaluating each
one in context and displaying the ones you choose.

\wxheading{Example}

\begin{verbatim}
   // Drop the table before attempting to create it
   sprintf(sqlStmt, "DROP TABLE %s", tableName);
   // Execute the drop table statement
   if (SQLExecDirect(hstmt,(UCHAR FAR *)sqlStmt,SQL_NTS) != SQL_SUCCESS)
   {
      // Check for sqlState = S0002, "Table or view not found".
      // Ignore this error, bomb out on any other error.
      pDb->GetNextError(henv, hdbc, hstmt);
      if (strcmp(pDb->sqlState, "S0002"))
      {
         pDb->DispNextError();   // Displayed error retrieved
         pDb->DispAllErrors(henv, hdbc, hstmt); // Display all other errors, if any
         pDb->RollbackTrans();   // Rollback the transaction
         CloseCursor();          // Close the cursor
         return(FALSE);          // Return Failure
      }
   }
\end{verbatim}


\membersection{wxDb::DropView}\label{wxdbdropview}

\func{bool}{DropView}{\param{const char *}{viewName}}

Drops the data table view named in 'viewName'.

\wxheading{Parameters}

\docparam{viewName}{Name of the view to be dropped.}

\wxheading{Remarks}

If the view does not exist, this function will return TRUE.  Note that views are not supported with all data sources.

\membersection{wxDb::ExecSql}\label{wxdbexecsql}

\func{bool}{ExecSql}{\param{char *}{pSqlStmt}}

Allows a native SQL command to be executed directly against the datasource.  In addition to being able to run any standard SQL command, use of this function allows a user to (potentially) utilize features specific to the datasource they are connected to that may not be available through ODBC.  The ODBC driver will pass the specified command directly to the datasource.

\wxheading{Parameters}

\docparam{pSqlStmt}{Pointer to the SQL statement to be executed.}

\wxheading{Remarks}

This member extends the wxDb class and allows you to build and execute ANY VALID
SQL statement against the data source.  This allows you to extend the class 
library by being able to issue any SQL statement that the data source is capable
of processing.

\wxheading{See also}

\helpref{wxDb::GetData}{wxdbgetdata}, \helpref{wxDb::GetNext}{wxdbgetnext}

\membersection{wxDb::FwdOnlyCursors}\label{wxdbfwdonlycursors}

\func{bool}{FwdOnlyCursors}{\void}

Indicates whether this connection to the datasource only allows forward scrolling cursors or not.  This state is set at connection creation time.

\wxheading{Remarks}

In wxWindows v2.4 release, this function will be deprecated to use a renamed version of the function called wxDb::IsFwdOnlyCursors() to match the normal wxWindows naming conventions for class member functions.

\wxheading{See also}

\helpref{wxDb::IsFwdOnlyCursors}{wxdbisfwdonlycursors}, \helpref{wxDb::wxDb}{wxdbconstr}, \helpref{wxDbGetConnection}{wxdbfunctions}

\membersection{wxDb::GetCatalog}\label{wxdbgetcatalog}

\func{wxDbInf *}{GetCatalog}{\param{char *}{userID}}

Returns a wxDbInf pointer that points to the catalog(data source) name, schema, number of tables accessible to the current user, and a wxDbTableInf pointer to all data pertaining to all tables in the users catalog.

\wxheading{Parameters}

\docparam{userID}{Owner of the table.  Specify a userID when the datasource you are connected to allows multiple unique tables with the same name to be owned by different users.  {\it userID} is evaluated as follows:}

\begin{verbatim}
         userID == NULL  ... UserID is ignored (DEFAULT)
         userID == ""    ... UserID set equal to 'this->uid'
         userID != ""    ... UserID set equal to 'userID'
\end{verbatim}

\wxheading{Remarks}

The returned catalog will only contain catalog entries for tables to which the user specified in 'userID' has sufficient privileges.  If no user is specified (NULL passed in), a catalog pertaining to all tables in the datasource accessible via this connection will be returned.

\membersection{wxDb::GetColumnCount}\label{wxdbgetcolumncount}

\func{int}{GetColumnCount}{\param{char *}{tableName}, \param{const char *}{userID}}

\wxheading{Parameters}

\docparam{tableName}{A table name you wish to obtain column information about.}

\docparam{userID}{Name of the user that owns the table(s).  Required for some datasources for situations where there may be multiple tables with the same name in the datasource, but owned by different users. {\it userID} is evaluated in the following manner:}

\begin{verbatim}
         userID == NULL  ... UserID is ignored (DEFAULT)
         userID == ""    ... UserID set equal to 'this->uid'
         userID != ""    ... UserID set equal to 'userID'
\end{verbatim}

\wxheading{Return value}

Returns a count of how many columns are in the specified table.  If an error occurs retrieving the number of columns the function will return a -1.

\membersection{wxDb::GetColumns}\label{wxdbgetcolumns}

\func{wxDbColInf *}{GetColumns}{\param{char *}{tableName}, \param{int *}{numCols}, \param{const char *}{userID=NULL}}

\func{wxDbColInf *}{GetColumns}{\param{char *}{tableName[]}, \param{const char *}{userID}}

\wxheading{Parameters}

\docparam{tableName}{A table name you wish to obtain column information about.}
\docparam{numCols}{A pointer to a integer which will hold a count of the number of columns returned by this function}
\docparam{tableName[]}{An array of pointers to table names you wish to obtain column information about.  The last element of this array must be a NULL string.}
\docparam{userID}{Name of the user that owns the table(s).  Required for some datasources for situations where there may be multiple tables with the same name in the datasource, but owned by different users. {\it userID} is evaluated in the following manner:}

\begin{verbatim}
         userID == NULL  ... UserID is ignored (DEFAULT)
         userID == ""    ... UserID set equal to 'this->uid'
         userID != ""    ... UserID set equal to 'userID'
\end{verbatim}

\wxheading{Return value}

This function returns an array of wxDbColInf structures.  This allows you to obtain
information regarding the columns of your table(s).  If no columns were found, or
an error occurred, this pointer will be zero (null).

THE CALLING FUNCTION IS RESPONSIBLE FOR DELETING THE {\it wxDbColInf} MEMORY WHEN IT IS
FINISHED WITH IT.

\normalbox{ALL column bindings associated with this wxDb instance are unbound
by this function.  This function should use its own wxDb instance
to avoid undesired unbinding of columns.}

\wxheading{See also}

\helpref{wxDbColInf}{wxdbcolinf}

\wxheading{Example}

\begin{verbatim}
   char *tableList[] = {"PARTS", 0};
   wxDbColInf *colInf = pDb->GetColumns(tableList);
   if (colInf)
   {
      // Use the column inf
      .......
      // Destroy the memory
      delete [] colInf;
   }
\end{verbatim}


\membersection{wxDb::GetData}\label{wxdbgetdata}

\func{bool}{GetData}{\param{UWORD}{ colNo}, \param{SWORD}{ cType}, \param{PTR}{ pData}, \param{SDWORD}{ maxLen}, \param{SDWORD FAR *}{ cbReturned} }

Used to retrieve result set data without binding column values to memory variables (i.e. not using a wxDbTable instance to access table data).

\wxheading{Parameters}

\docparam{colNo}{Ordinal number of column in the result set to be returned.}
\docparam{cType}{The C data type that is to be returned.}
\docparam{pData}{Memory buffer which will hold the data returned by the call to this function.}
\docparam{maxLen}{Maximum size of the buffer that will hold the returned value.}
\docparam{cbReturned}{Pointer to the buffer containing the length of the actual data returned.  If this value comes back as SQL_NULL_DATA, then the GetData() call has failed.}

\wxheading{See also}

\helpref{wxDb::GetNext}{wxdbgetnext}, \helpref{wxDb::ExecSql}{wxdbexecsql}

\wxheading{Example} 

\begin{verbatim}
    SDWORD cb;
    ULONG reqQty;
    wxString sqlStmt;
    sqlStmt = "SELECT SUM(REQUIRED_QTY - PICKED_QTY) FROM ORDER_TABLE WHERE \
                 PART_RECID = 1450 AND REQUIRED_QTY > PICKED_QTY";

    // Perform the query
    if (!pDb->ExecSql(sqlStmt.c_str()))
    {
        // ERROR
        return(0);
    }

    // Request the first row of the result set
    if (!pDb->GetNext())
    {
        // ERROR
        return(0);
    }

    Read column #1 of this row of the result set and store the value in 'reqQty'
    if (!pDb->GetData(1, SQL_C_ULONG, &reqQty, 0, &cb))
    {
        // ERROR
        return(0);
    }

    // Check for a NULL result
    if (cb == SQL_NULL_DATA)
        return(0);
\end{verbatim}

\wxheading{Remarks}

When requesting multiple columns to be returned from the result set (for example, the SQL query
requested 3 columns be returned), the calls to this function must request the columns in ordinal
sequence (1,2,3 or 1,3 or 2,3).  

\membersection{wxDb::GetDatabaseName}\label{wxdbgetdatabasename}

\func{const char *}{GetDatabaseName}{\void}

Returns the name of the database engine.

\membersection{wxDb::GetDataSource}\label{wxdbgetdatasource}

\func{const char *}{GetDataSource}{\void}

Returns the ODBC datasource name.

\membersection{wxDb::GetHDBC}\label{wxdbgethdbc}

\func{HDBC}{GetHDBC}{\void}

Returns the ODBC handle to the database connection.

\membersection{wxDb::GetHENV}\label{wxdbgethenv}

\func{HENV}{GetHENV}{\void}

Returns the ODBC environment handle.

\membersection{wxDb::GetHSTMT}\label{wxdbgethstmt}

\func{HSTMT}{GetHSTMT}{\void}

Returns the ODBC statement handle associated with this database connection.

\membersection{wxDb::GetKeyFields}\label{wxdbgetkeyfields}

\func{int}{GetKeyFields}{\param{char *}{tableName}, \param{wxDbColInf *}{colInf}, \param{int}{nocols}}

Used to determine which columns are members of primary or non-primary indexes on the specified table.  If a column is a member of a foreign key for some other table, that information is detected also.

This function is primarily for use by the \helpref{wxDb::GetColumns}{wxdbgetcolumns} function, but may be called if desired from the client application.

\wxheading{Parameters}

\docparam{tableName}{Name of the table for which the columns will be evaluated as to their inclusion in any indexes.}
\docparam{colInf}{Data structure containing the column definitions (obtained with \helpref{wxDb::GetColumns}{wxdbgetcolumns}).  This function populates the PkCol, PkTableName, and FkTableName members of the colInf structure.}
\docparam{nocols}{Number of columns defined in the instance of colInf.}

\wxheading{Return value}

Currently always returns TRUE.

\wxheading{See also}

\helpref{wxDbColInf}{wxdbcolinf}, \helpref{wxDb::GetColumns}{wxdbgetcolumns}

\membersection{wxDb::GetNext}\label{wxdbgetnext}

\func{bool}{GetNext}{\void}

Requests the next row in the result set obtained by issuing a query through a direct request using wxDb::ExecSql().

\wxheading{See also}

\helpref{wxDb::ExecSql}{wxdbexecsql}, \helpref{wxDb::GetData}{wxdbgetdata}

\membersection{wxDb::GetNextError}\label{wxdbgetnexterror}

\func{bool}{GetNextError}{\param{HENV}{ aHenv}, \param{HDBC}{ aHdbc = SQL_NULL_HDBC}, \param{HSTMT}{ aHstmt = SQL_NULL_HSTMT}}

\wxheading{Parameters}

\docparam{aHenv}{A handle to the ODBC environment.}
\docparam{aHdbc}{A handle to the ODBC connection.  Pass this in if the ODBC function call that
erred out required a hdbc or hstmt argument.}
\docparam{AHstmt}{A handle to the ODBC statement being executed against.  Pass this in if the
ODBC function call that erred out requires a hstmt argument.}

\wxheading{See also}

\helpref{wxDb::DispNextError}{wxdbdispnexterror}, \helpref{wxDb::DispAllErrors}{wxdbdispallerrors}

\wxheading{Example} 

\begin{verbatim}
   if (SQLExecDirect(hstmt, (UCHAR FAR *) pSqlStmt, SQL_NTS) != SQL_SUCCESS)
   {
      // Display all ODBC errors for this stmt
      return(db.DispAllErrors(db.henv, db.hdbc, hstmt));
   }
\end{verbatim}


\membersection{wxDb::GetPassword}\label{wxdbgetpassword}

\func{const char *}{GetPassword}{\void}

Returns the password used to connect to the datasource.

\membersection{wxDb::GetTableCount}\label{wxdbgettablecount}

\func{int}{GetTableCount}{\void}

Returns the number of wxDbTable() instances currently using this data source connection.


\membersection{wxDb::GetUsername}\label{wxdbgetusername}

\func{const char *}{GetUsername}{\void}

Returns the user name used to access the datasource.


\membersection{wxDb::Grant}\label{wxdbgrant}

\func{bool}{Grant}{\param{int}{ privileges}, \param{char *}{tableName}, \param{char *}{userList = "PUBLIC"}}

Use this member function to GRANT privileges to users for accessing tables in the datasource.

\wxheading{Parameters}

\docparam{privileges}{Use this argument to select which privileges you want to grant.  Pass DB_GRANT_ALL to grant all privileges.  To grant individual privileges pass one or more of the following OR'd together:}

\begin{verbatim}
         DB_GRANT_SELECT  = 1
         DB_GRANT_INSERT  = 2
         DB_GRANT_UPDATE  = 4
         DB_GRANT_DELETE  = 8
         DB_GRANT_ALL     = DB_GRANT_SELECT | DB_GRANT_INSERT |
                            DB_GRANT_UPDATE | DB_GRANT_DELETE
\end{verbatim}

\docparam{tableName}{The name of the table you wish to grant privileges on.}
\docparam{userList}{A comma delimited list of users to grant the privileges to.  If this argument is not passed in, the privileges will be given to the general PUBLIC.}

\wxheading{Remarks}

Some databases require user names to be specified in all capital letters (i.e. Oracle).  This function does not automatically capitalize the user names passed in the comma-separated list.  This is the responsibility of the calling routine.

\wxheading{Example} 

\begin{verbatim}
   db.Grant(DB_GRANT_SELECT | DB_GRANT_INSERT, "PARTS", "mary, sue");
\end{verbatim}


\membersection{wxDb::IsFwdOnlyCursors}\label{wxdbisfwdonlycursors}

\func{bool}{IsFwdOnlyCursors}{\void}

This setting indicates whether this database connection was created
as being capable of using only forward scrolling cursors.  This function
does NOT indicate if the ODBC driver or datasource supports backward
scrolling cursors.  There is no standard way of detecting if the driver
or datasource can support backward scrolling cursors.

If a wxDb instance was created as being forward only cursors, then even if
the datasource and ODBC driver support backward scrolling cursors, then
tables using this database connection can only use forward scrolling
cursors.

The default setting of whether a wxDb connection to a database allows
forward-only or also backward scrolling cursors is defined in setup.h by 
the wxODBC_FWD_ONLY_CURSORS value.  This default setting can be overridden
when the wxDb connection is initially created (see \helpref{wxDb constructor}{wxdbconstr}).

\wxheading{Return value}

Returns TRUE if this datasource connection is defined as using only forward
scrolling cursors, or FALSE if the connection is defined as being capable
of supporting backward scrolling cursors (see note above).

\wxheading{Remarks}

Added as of wxWindows v2.4 release, this function is a renamed version of 
wxDb::FwdOnlyCursors() to match the normal wxWindows naming conventions for 
class member functions.

This function is not available in versions prior to v2.4.  You should use \helpref{wxDb::FwdOnlyCursors}{wxdbfwdonlycursors} for wxWindows versions priori to 2.4.

\wxheading{See also}

\helpref{wxDb constructor}{wxdbconstr}, \helpref{wxDbGetConnection}{wxdbfunctions}


\membersection{wxDb::IsOpen}\label{wxdbisopen}

\func{bool}{IsOpen}{\void}

Indicates whether the database connection to the datasource is currently 
opened.

\wxheading{Remarks}

This function may indicate that the database is open, but the call to 
\helpref{wxDb::Open}{wxdbopen} may have failed to fully initialize the connection
correctly.  The connection to the database {\it is} open and can be used via
the direct SQL commands, but other functions which depend on the \helpref{wxDb::Open}{wxdbopen}
to have completed correctly may not function as expected.  See \helpref{wxDb::Open}{wxdbopen}
for more details on partial failures to open a connection instance.


\membersection{wxDb::LogError}\label{wxdblogerror}

\func{void}{LogError}{\param{const char *}{errMsg} \param{const char *}{SQLState=0}}

\docparam{errMsg}{Free-form text to display describing the error to be logged.}
\docparam{SQLState}{Native SQL state error}

\wxheading{Remarks}

Calling this function will enter a log message in the error list maintained
for the database connection.  This log message is free form and can be
anything the programmer wants to enter in the error list.

If SQL logging is turned on, the call to this function will also log the
text into the SQL log file.

\wxheading{See also}

\helpref{wxDb::WriteSqlLog}{wxdbwritesqllog}


\membersection{wxDb::Open}\label{wxdbopen}

\func{bool}{Open}{\param{char *}{Dsn}, \param{char *}{Uid}, \param{char *}{AuthStr}}
\func{bool}{Open}{\param{wxDb *}{copyDb}}

Opens a connection to the datasource, sets behaviors of all databases to 
confirm to the accepted behaviors (e.g. cursor position maintained on commits), 
and queries the datasource for its representations of the basic datatypes to 
determine the form that data going to/from columns in the data tables are 
to be handled.

The second form of this function which accepts a "wxDb *" as a parameter 
can be used to avoid the overhead (execution time, database load, network 
traffic) which are needed to determine the data types and representations 
of data that are necessary for cross-datasource support by these classes.  
Normally the first form of the wxDb::Open() function will open the connection 
and then send a series of queries to the datasource asking it for its 
representation of data types, and all the features it supports.  If one 
connection to the datasource has already been made previously, the information 
gathered when that connection was created can just be copied to any new 
connections to the same datasource by passing a pointer to the first 
connection in as a parameter to the wxDb::Open() function.  Note that this 
new connection created from the first connections information will use the 
same Dsn/Uid/AuthStr as the first connection used.

\wxheading{Parameters}

\docparam{Dsn}{Data source name.  The name of the ODBC data source as 
assigned when the data source is initially set up through the ODBC data 
source manager.}
\docparam{Uid}{User ID.  The name (ID) of the user you wish to connect as
to the data source.  The user name (ID) determines what objects you
have access to in the datasource and what datasource privileges you have.
Privileges include being able to create new objects, update objects, delete
objects and so on.  Users and privileges are normally administered by the
database administrator.}
\docparam{AuthStr}{The password associated with the Uid.}
\docparam{copyDb}{Already completely configured and opened datasource 
connection from which all Dsn, Uid, AuthStr, and data typing information is 
to be copied from for use by this datasource connection.}

\wxheading{Remarks}

After a wxDb instance is created, it must then be opened.  When opening a 
data source, there must be hree pieces of information passed.  The data 
source name, user name (ID) and the password for the user.  No database 
activity on the data source can be performed until it is opened.  This 
would normally be done at program startup and the data source would remain 
open for the duration of the program run.  

It is possible to have multiple data sources open at the same time to 
support distributed database connections by having separate instances of wxDb 
objects that use different Dsn/Uid/AuthStr settings.

If this function returns a value of FALSE, it does not necessarily mean that 
the connection to the datasource was not opened.  It may mean that some 
portion of the initialization of the connection failed (such as a datatype not 
being able to be determined how the datasource represents it).  To determine 
if the connection to the database failed, use the \helpref{wxDb::IsOpen}{wxdbisopen} 
function after receiving a FALSE result back from this function to determine if 
the connection was opened or not.  If this function returns FALSE, but \helpref{wxDb::IsOpen}{wxdbisopen} 
returns TRUE, then direct SQL commands may be passed to the database 
connection and they can be successfully executed, but use of the datatypes 
that are normally determined during open will not be accessible to any 
wxDbTable objects using this connection.

\wxheading{Example}

\begin{verbatim}
   wxDb sampleDB(Db.Henv);
   if (!sampleDB.Open("Oracle 7.1 HP/UX", "gtasker", "myPassword"))
   {
      // Error opening data source
   }
\end{verbatim}


\membersection{wxDb::RollbackTrans}\label{wxdbrollbacktrans}

\func{bool}{RollbackTrans}{\void}

Function to "rollback" changes made to the database.  After an insert/update/delete, the operation may be "undone" by issuing this command any time before a \helpref{wxDb::CommitTrans}{wxdbcommittrans} is called on the database connection.

\wxheading{Remarks}

Transactions begin implicitly as soon as you make a change to the database.  At any time thereafter, you can save your work to the database (using \helpref{wxDb::CommitTrans}{wxdbcommittrans}) or undo all of your changes using this function.

\normalbox{Calling this member function rolls back ALL open (uncommitted) transactions on this ODBC connection.}

\wxheading{See also}

\helpref{wxDb::CommitTrans}{wxdbcommittrans} for a special note on cursors


\membersection{wxDb::SetDebugErrorMessages}\label{wxdbsetdebugerrormessages}

\func{void}{SetDebugErrorMessages}{\param{bool }{state}}

\docparam{state}{Either TRUE (debug messages are displayed) or FALSE (debug
messages are not displayed.}

\wxheading{Remarks}

Turns on/off debug error messages from the ODBC class library.  When
this function is passed TRUE, errors are reported to the user automatically
in a text or pop-up dialog when an ODBC error occurs.  When passed FALSE,
errors are silently handled.

When compiled in release mode (FINAL=1), this setting has no affect.

\wxheading{See also}

\helpref{wxDb constructor}{wxdbconstr}


\membersection{wxDb::SetSqlLogging}\label{wxdbsetsqllogging}

\func{bool}{SetSqlLogging}{\param{wxDbSqlLogState}{ state}, \param{const wxChar *}{filename = SQL_LOG_FILENAME}, \param{bool }{ append = FALSE}}

\wxheading{Parameters}

\docparam{state}{Either sqlLogOFF or sqlLogON (see \helpref{enum wxDbSqlLogState}{wxdbcolfor}). Turns logging of SQL commands sent to the data source OFF or ON.}
\docparam{filename}{{\it OPTIONAL}.  Name of the file to which the log text is to be written.}
\docparam{append}{{\it OPTIONAL}. Whether the file is appended to or overwritten.}

\wxheading{Remarks}

When called with {\it sqlLogON}, all commands sent to the data source engine are logged to the file specified by {\it filename}.  Logging is done by embedded WriteSqlLog() calls in the database member functions, or may be manually logged by adding calls to WriteSqlLog() in your own source code.

When called with {\it sqlLogOFF}, the logging file is closed, and any calls to WriteSqlLog() are ignored.


\membersection{wxDb::TableExists}\label{wxdbtablexists}

\func{bool}{TableExists}{\param{const char *}{tableName}, \param{const char *}{userID=NULL}, \param{const char *}{path=NULL}}

Checks the ODBC data source for the existence of a table.  If a {\it userID} 
is specified, then the table must be accessible by that user (user must have 
at least minimal privileges to the table).

\wxheading{Parameters}

\docparam{tableName}{Name of the table to check for the existence of}
\docparam{userID}{Owner of the table.  Specify a userID when the datasource you are connected
to allows multiple unique tables with the same name to be owned by different users.  {\it userID}
is evaluated as follows:}

\begin{verbatim}
         userID == NULL  ... UserID is ignored (DEFAULT)
         userID == ""    ... UserID set equal to 'this->uid'
         userID != ""    ... UserID set equal to 'userID'
\end{verbatim}

\wxheading{Remarks}

{\it tableName} may refer to a table, view, alias or synonym.

This function does not indicate whether or not the user has privileges to query or perform other functions on the table.

\wxheading{See also}

\helpref{wxDb::TablePrivileges}{wxdbtableprivileges}


\membersection{wxDb::TablePrivileges}\label{wxdbtableprivileges}

\func{bool}{TablePrivileges}{\param{const char *}{tableName}, \param{const char *}{priv}, \param{const char *}{userID=NULL}, \param{const char *}{path=""}}

Checks the ODBC data source for the existence of a table.  If a {\it userID} 
is specified, then the table must be accessible by that user (user must have 
at least minimal privileges to the table).

\wxheading{Parameters}

\docparam{tableName}{Name of the table on which to check privileges.  
{\it tableName} may refer to a table, view, alias or synonym.}
\docparam{priv}{The table privilege being evaluated. May be one of the 
following (or a data source specific privilege):}

\begin{verbatim}
    SELECT      : The connected user is permitted to retrieve data for one 
                  or more columns of the table.

    INSERT      : The connected user is permitted to insert new rows 
                  containing data for one or more columns into the table.

    UPDATE      : The connected user is permitted to update the data in one 
                  or more columns of the table.

    DELETE      : The connected user is permitted to delete rows of data 
                  from the table.

    REFERENCES  : Is the connected user permitted to refer to one or more 
                  columns of the table within a constraint (for example, a 
                  unique, referential, or table check constraint).
\end{verbatim}
\docparam{userID}{Owner of the table.  Specify a userID when the datasource 
you are connected to allows multiple unique tables with the same name to be 
owned by different users.  {\it userID} is evaluated as follows:

\begin{verbatim}
         userID == NULL  ... UserID is ignored (DEFAULT)
         userID == ""    ... UserID set equal to 'this->uid'
         userID != ""    ... UserID set equal to 'userID'
\end{verbatim}
}
\docparam{path}{{\it OPTIONAL.}  Path to the table.  Default is "".  
Currently unused.}

\wxheading{Remarks}

The scope of privilege allowed to the connected user by a given table 
privilege is data source dependent. 

For example, the privilege UPDATE might allow the connected user to update 
all columns in a table on one data source, but only those columns for 
which the grantor (the user that granted the connected user) has the UPDATE 
privilege on another data source.


\membersection{wxDb::TranslateSqlState}\label{wxdbtranslatesqlstate}

\func{int}{TranslateSqlState}{\param{const wxChar *}{SQLState}}

\wxheading{Parameters}

\docparam{SQLState}{Converts an ODBC sqlstate to an internal error code.}

\wxheading{Return value}

Returns the internal class DB_ERR code.  See \helpref{wxDb::DB_STATUS}{wxdb} definition.


\membersection{wxDb::WriteSqlLog}\label{wxdbwritesqllog}

\func{bool}{WriteSqlLog}{\param{const wxChar *}{logMsg}}

\wxheading{Parameters}

\docparam{logMsg}{Free form string to be written to the log file.}

\wxheading{Remarks}

Very useful debugging tool that may be turned on/off during run time.  The
passed in string {\it logMsg} will be written to a log file if SQL logging
is turned on (see \helpref{wxDb::SetSqlLogging}{wxdbsetsqllogging} for details on turning logging on/off).

\wxheading{Return value}

If SQL logging is off when a call to WriteSqlLog() is made, or there is a
failure to write the log message to the log file, the function returns
FALSE without performing the requested log, otherwise TRUE is returned.

\wxheading{See also}

\helpref{wxDb::SetSqlLogging}{wxdbsetsqllogging}


\section{\class{wxDbColDataPtr}}\label{wxdbcoldataptr}

Pointer to dynamic column definitions for use with a wxDbTable instance.  
Currently there are no member functions for this class.

\begin{verbatim}
    void   *PtrDataObj;
    int     SzDataObj;
    int     SqlCtype;
\end{verbatim}


\section{\class{wxDbColDef}}\label{wxdbcoldef}

This class is used to hold information about the columns bound to an 
instance of a wxDbTable object.  

Each instance of this class describes one column in the wxDbTable 
object.  When calling the \helpref{wxDb constructor}{wxdbconstr}, a 
parameter passed in indicates the number of columns that will be defined for 
the wxDbTable object.  The constructor uses this information to allocate 
adequate memory for all of the column descriptions in your wxDbTable object.  
Private member wxDbTable::colDefs is a pointer to this chunk of memory 
maintained by the wxDbTable class (and can be retrieved using the 
\helpref{wxDbTable::GetColDefs}{wxdbtablegetcoldefs} function).  
To access the nth column definition of your wxDbTable object, just reference 
wxDbColDefs element [n - 1].

Currently there are no member functions for this class.

Typically, \helpref{wxDbTable::SetColDefs}{wxdbtablesetcoldefs} takes care of 
populating an array of these data structures for the wxDbTable instance.

\begin{verbatim}
    char    ColName[DB_MAX_COLUMN_NAME_LEN+1];  // Column Name
    int     DbDataType;    - Logical Data Type; e.g. DB_DATA_TYPE_INTEGER
    int     SqlCtype;      - C data type; e.g. SQL_C_LONG
    void   *PtrDataObj;    - Address of the data object
    int     SzDataObj;     - Size, in bytes, of the data object
    bool    KeyField;      - Is column part of the PRIMARY KEY for the
                             table? -- Date fields should NOT be KeyFields
    bool    Updateable;    - Column is updateable?
    bool    InsertAllowed; - Column included in INSERT statements?
    bool    DerivedCol;    - Column is a derived value?
    SDWORD  CbValue;       - !!!Internal use only!!!
    bool    Null;          - NOT FULLY IMPLEMENTED
                             Allows NULL values in Inserts and Updates
\end{verbatim}

\wxheading{See also}

\helpref{wxDbTable::GetColDefs}{wxdbtablegetcoldefs}, \helpref{wxDb constructor}{wxdbconstr}


\section{\class{wxDbColInf}}\label{wxdbcolinf}

Used with the \helpref{wxDb::GetColumns}{wxdbgetcolumns} functions for obtaining all retrievable information about a columns definition.


\section{\class{wxDbColFor}}\label{wxdbcolfor}

Beginning support for handling international formatting specifically on dates and floats.  

Only one function is provided with this class currently:

\membersection{wxDbColFor::Format}\label{wxdbcolforformat}

\func{int}{Format}{\param{int }{Nation}, \param{int }{dbDataType}, \param{SWORD }{sqlDataType}, \param{short }{columnSize}, \param{short }{decimalDigits}}\label{wxdbcolforformat}

Work in progress, and should be inter-related with wxLocale


\section{\class{wxDbIdxDef}}\label{wxdbidxdef}

Used in creation of non-primary indexes.  Currently there are no member 
functions for this class.

\begin{verbatim}
        char    ColName[DB_MAX_COLUMN_NAME_LEN+1] - Name of column
        bool    Ascending  - Are the values in the index in ASCENDING sequence?
\end{verbatim}


\section{\class{wxDbInf}}\label{wxdbinf}

Contains information regarding the database connection (data source name, 
number of tables, etc).  A pointer to a wxDbTableInf is included in this 
class so a program can create a wxDbTableInf array instance to maintain all
information about all tables in the datasource to have all the datasource's
information in one memory structure.


\section{\class{wxDbTable}}\label{wxdbtable}

A wxDbTable instance provides re-usable access to rows of data in
a table contained within the associated ODBC data source

\wxheading{Include files}

<wx/dbtable.h>\\
<wx/db.h>

\latexignore{\rtfignore{\wxheading{Members}}}
\wxheading{Helper classes and data structures}

The following classes and structs are defined in dbtable.cpp/.h for use with the wxDbTable class.
\begin{itemize}\itemsep=0pt
\item \helpref{wxDbColDef}{wxdbcoldef}
\item \helpref{wxDbColDataPtr}{wxdbcoldataptr}
\item \helpref{wxDbIdxDef}{wxdbidxdef}
\end{itemize}

\wxheading{Constants}

\begin{verbatim}
    wxDB_DEFAULT_CURSOR     Index number of the cursor that each table will use
                            by default.

    wxDB_QUERY_ONLY         Used to indicate whether a table that is opened is
                            for query only, or if insert/update/deletes will
                            be performed on the table.  Less overhead (cursors
                            and memory) are allocated for query only tables, plus
                            read access times are faster with some datasources.

    wxDB_ROWID_LEN          [Oracle specific] - Used when CanUpdateByRowID() is
                            true.  Optimizes updates so they are faster by 
                            updating on the Oracle-specific ROWID column rather 
                            than some other index.


    wxDB_DISABLE_VIEW       Use to indicate when a database view should not be
                            if a table is normally set up to use a view.  
                            [Currently unsupported.]

\end{verbatim}

\wxheading{See also}

\helpref{wxDbTable}{wxdbtable}

\latexignore{\rtfignore{\wxheading{Members}}}

\membersection{wxDbTable::wxDbTable}\label{wxdbtableconstr}

\func{}{wxDbTable}{\param{wxDb *}{pwxDb}, \param{const char *}{tblName}, \param{const int }{nCols}, \param{const char *}{qryTblName = 0}, \param{bool }{qryOnly = !wxDB_QUERY_ONLY}, \param{const char *}{tblPath=NULL}}

Default constructor.

\wxheading{Parameters}

\docparam{pwxDb}{Pointer to the wxDb instance to be used by this wxDbTable 
instance.}
\docparam{tblName}{The name of the table in the RDBMS.}
\docparam{nCols}{The number of columns in the table.  (Do NOT include the ROWID
column in the count if using Oracle).}
\docparam{qryTblName}{{\it OPTIONAL}.  The name of the table or view to base 
your queries on.  This argument allows you to specify a table/view other than
the base table for this object to base your queries on.  This allows you to 
query on a view for example, but all of the INSERT, UPDATE and DELETES will 
still be performed on the base table for this wxDbTable object.  Basing your 
queries on a view can provide a substantial performance increase in cases where
your queries involve many tables with many joins.  Default is 0 (NULL)}
\docparam{qryOnly}{{\it OPTIONAL}.  Indicates whether the table will be 
accessible for query purposes only, or should the table create the necessary
cursors to be able to insert, update, and delete data from the table.  
Default is !wxDB_QUERY_ONLY.}
\docparam{tblPath}{{\it OPTIONAL}.  Some data sources (such as dBase) 
require a path to where the table is stored on the system.  Default is NULL.}

\membersection{wxDbTable::wxDbTable}\label{wxdbtabledestr}

\func{virtual}{\destruct{wxDbTable}}{}

Virtual default destructor.


\membersection{wxDbTable::BuildDeleteStmt}\label{wxdbtablebuilddeletestmt}

\func{void}{BuildDeleteStmt}{\param{char *}{pSqlStmt}, \param{int }{typeOfDel}, \param{const char *}{pWhereClause=0}}

Constructs the full SQL statement that can be used to delete all rows matching
the criteria in the pWhereClause.

\wxheading{Parameters}

\docparam{pSqlStmt}{Pointer to storage for the SQL statement retrieved.  To be
sure you have adequate space allocated for the SQL statement, allocate
DB_MAX_STATEMENT_LEN bytes.}
\docparam{typeOfDel}{The type of delete statement being performed.  Can be one
of three values: DB_DEL_KEYFIELDS, DB_DEL_WHERE or DB_DEL_MATCHING}
\docparam{pWhereClause}{{\it OPTIONAL}.  If the typeOfDel is DB_DEL_WHERE, 
then you must also pass in a SQL WHERE clause in this argument.  Default 
is 0 (NULL).}

\wxheading{Remarks}

This member function allows you to see what the SQL DELETE statement looks like
that the ODBC class library builds.  This can be used for debugging purposes if
you are having problems executing your SQL statement.

WHERE and FROM clauses specified in \helpref{wxDbTable::SetWhereClause}{wxdbtablesetwhereclause} 
and \helpref{wxDbTable::SetFromClause}{wxdbtablesetfromclause} are ignored by 
this function.


\membersection{wxDbTable::BuildSelectStmt}\label{wxdbtablebuildselectstmt}

\func{void}{BuildSelectStmt}{\param{char *}{pSqlStmt}, \param{int }{typeOfSelect}, \param{bool }{distinct}}

Constructs the full SQL statement that can be used to select all rows matching
the criteria in the pWhereClause.  Internal to the wxDbTable class, this 
function is called whenever the function \helpref{wxDbTable::Query}{wxdbtablequery}
is called.

NOTE: Only the columns specified in \helpref{wxDbTable::SetColDefs}{wxdbtablesetcoldefs}
statements are included in the list of columns returned by the SQL statement 
created by a call to this function.

\wxheading{Parameters}

\docparam{pSqlStmt}{Pointer to storage for the SQL statement retrieved.  To be
sure you have adequate space allocated for the SQL statement, allocate
DB_MAX_STATEMENT_LEN bytes.}
\docparam{typeOfSelect}{The type of select statement being performed.  Can be
one of four values: DB_SELECT_KEYFIELDS, DB_SELECT_WHERE, DB_SELECT_MATCHING
or DB_SELECT_STATEMENT.}
\docparam{distinct}{Whether to select distinct records only.}

\wxheading{Remarks}

This member function allows you to see what the SQL SELECT statement looks like
that the ODBC class library builds.  This can be used for debugging purposes if
you are having problems executing your SQL statement.

WHERE and FROM clauses specified in \helpref{wxDbTable::SetWhereClause}{wxdbtablesetwhereclause} 
and \helpref{wxDbTable::SetFromClause}{wxdbtablesetfromclause} are ignored by 
this function.


\membersection{wxDbTable::BuildUpdateStmt}\label{wxdbtablebuildupdatestmt}

\func{void}{BuildSelectStmt}{\param{char *}{pSqlStmt}, \param{int }{typeOfUpd}, \param{const char *}{pWhereClause=0}}

Constructs the full SQL statement that can be used to update all rows matching
the criteria in the pWhereClause.

If typeOfUpd is DB_UPD_KEYFIELDS, then the current values in the bound columns
are used to determine which row(s) in the table are to be updated. The 
exception to this is when a data source supports ROW IDs (Oracle).  The ROW ID
column is used for efficiency purposes when available.

NOTE: Only the columns specified in \helpref{wxDbTable::SetColDefs}{wxdbtablesetcoldefs}
statements are included in the list of columns updated by the SQL statement 
created by a call to this function.  Any column definitions that were defined
as being non-updateable will be excluded from the SQL UPDATE statement created
by this function.

\wxheading{Parameters}

\docparam{pSqlStmt}{Pointer to storage for the SQL statement retrieved.  To be
sure you have adequate space allocated for the SQL statement, allocate
DB_MAX_STATEMENT_LEN bytes.}
\docparam{typeOfUpd}{The type of update statement being performed.  Can be one
of two values: DB_UPD_KEYFIELDS or DB_UPD_WHERE.}
\docparam{pWhereClause}{{\it OPTIONAL}.  If the typeOfUpd is DB_UPD_WHERE, 
then you must also pass in a SQL WHERE clause in this argument.  Default 
is 0 (NULL).}

\wxheading{Remarks}

This member function allows you to see what the SQL UPDATE statement looks like
that the ODBC class library builds.  This can be used for debugging purposes if
you are having problems executing your SQL statement.

WHERE and FROM clauses specified in \helpref{wxDbTable::SetWhereClause}{wxdbtablesetwhereclause} 
and \helpref{wxDbTable::SetFromClause}{wxdbtablesetfromclause} are ignored by 
this function.


\membersection{wxDbTable::BuildWhereStmt}\label{wxdbtablebuildwherestmt}

\func{void}{BuildSelectStmt}{\param{char *}{pWhereClause}, \param{int }{typeOfWhere}, \param{const char *}{qualTableName=0}, \param{const char *}{useLikeComparison=FALSE}}

Constructs the portion of a SQL statement which would follow the word 'WHERE'
in the SQL statement to be passed to the data source.  The returned string
does NOT include the word 'WHERE'.

\wxheading{Parameters}

\docparam{pWhereClause}{Pointer to storage for the SQL statement retrieved.  
To be sure you have adequate space allocated for the SQL statement, allocate
DB_MAX_STATEMENT_LEN bytes.}
\docparam{typeOfWhere}{The type of where clause to generate.  Can be one of 
two values:  DB_WHERE_KEYFIELDS or DB_WHERE_MATCHING.}
\docparam{qualTableName}{{\it OPTIONAL}.  Prepended to all base table 
column names.  For use when a FROM clause has been specified with the 
\helpref{wxDbTable::SetFromClause}{wxdbtablesetfromclause}, 
to clarify which table a column name reference belongs to.  Default is 0 
(NULL).}
\docparam{useLikeComparison}{{\it OPTIONAL}.  Should the constructed WHERE 
clause utilize the LIKE comparison operator.  If FALSE, then the '=' 
operator is used.  Default is FALSE.}

\wxheading{Remarks}

This member function allows you to see what the SQL WHERE clause looks like 
that the ODBC class library builds.  This can be used for debugging purposes
if you are having problems executing your SQL statements.

If using 'typeOfWhere' set to DB_WHERE_MATCHING, any bound columns currently
containing a NULL value are not included in the WHERE clause's list of
columns to use in the comparison.


\membersection{wxDbTable::CanSelectForUpdate}\label{wxdbtablecanselectforupdate}

\func{bool}{CanSelectForUpdate}{\void}

Use this function to determine if the data source supports SELECT ... FOR UPDATE.
When the keywords "FOR UPDATE" are included as part of your SQL SELECT statement,
all records retrieved from the query are locked.  

\wxheading{Remarks}

Not all data sources support the "FOR UPDATE" clause, so you must use this
member function to determine if the data source currently connected to supports
this behavior or not before trying to select using "FOR UPDATE".


\membersection{wxDbTable::CanUpdateByROWID}\label{wxdbtablecanupdatebyrowid}

\func{bool}{CanUpdateByROWID}{\void}

CURRENTLY ONLY POSSIBLE IF USING ORACLE.  

--- CURRENTLY DISABLED FOR *ALL* DATASOURCES --- NOV 1 2000 - gt

Every Oracle table has a hidden column named ROWID.  This is a pointer to the
physical location of the record in the data store and allows for very fast 
updates and deletes.  The key is to retrieve this ROWID during your query so
it is available during an update or delete operation. 

This is always handled by the class library except in the case of 
QueryBySqlStatement().  Since you are passing in the SQL SELECT statement, 
it is up to you to include the ROWID column in your query.  If you do not, 
the application will still work, but may not be as optimized.  The ROWID is 
always the last column in the column list in your SQL SELECT statement.  
The ROWID is not a column in the normal sense and should not be considered 
part of the column definitions for the wxDbTable object.

\wxheading{Remarks}

The decision to include the ROWID in your SQL SELECT statement must be 
deferred until runtime since it depends on whether you are connected 
to an Oracle data source or not.

\wxheading{Example}

\begin{verbatim}
    // Incomplete code sample
    wxDbTable parts;
    .....
    if (parts.CanUpdByROWID())
    begin
        // Note that the ROWID column must always be the last column selected
        sqlStmt = "SELECT PART_NO, PART_DESC, ROWID" FROM PARTS";
    end
    else
        sqlStmt = "SELECT PART_NO, PART_DESC" FROM PARTS";
\end{verbatim}


\membersection{wxDbTable::ClearMemberVars}\label{wxdbtableclearmembervars}

\func{void}{ClearMemberVars}{\void}

Initializes all of the bound columns of the wxDbTable instance to zero.  
In the case of a string, zero is copied to the first byte of the string.  

\wxheading{Remarks}

This is useful before calling \helpref{wxDbTable::QueryMatching}{wxdbtablequerymatching} or 
\helpref{wxDbTable::DeleteMatching}{wxdbtabledeletematching} since these 
functions build their WHERE clauses from non-zero columns.  To call either 
\helpref{wxDbTable::QueryMatching}{wxdbtablequerymatching} or 
\helpref{wxDbTable::DeleteMatching}{wxdbtabledeletematching} use this sequence:

\begin{verbatim}
1)  ClearMemberVars()
2)  Assign columns values you wish to match on
3)  Call wxDbTable::QueryMatching() or wxDbTable::DeleteMatching()
\end{verbatim}

\membersection{wxDbTable::CloseCursor}\label{wxdbtableclosecursor}

\func{bool}{CloseCursor}{\param{HSTMT}{cursor}}

Closes the specified cursor associated with the wxDbTable object.

\wxheading{Parameters}

\docparam{cursor}{The cursor to be closed.}

\wxheading{Remarks}

Typically handled internally by the ODBC class library, but may be used by the 
programmer if desired.


\membersection{wxDbTable::Count}\label{wxdbtablecount}

\func{ULONG}{Count}{\param{const char *}{args="*"}}

Returns the number of records which would be in the result set using the
current query parameters specified in the WHERE and FROM clauses.

\wxheading{Parameters}

\docparam{args}{{\it OPTIONAL}.  This arguement allows the use of the 
DISTINCT keyword against a column name to cause the returned count to 
only indicate the number of rows in the result set that have a unique 
value in the specified column.  An example is shown below.  Default is "*", 
meaning a count of the total number of rows is returned, regardless of 
uniqueness.}

\wxheading{Remarks}

This function can be called before or after an actual query to obtain the 
count of records in the result set.  Count() uses its own cursor, so result
set cursor positioning is not affected by calls to Count().

\wxheading{Example}

\begin{verbatim}

    USERS TABLE

    FIRST_NAME      LAST_NAME
    -----------     ----------
    John            Doe    
    Richard         Smith
    Michael         Jones
    John            Carpenter

    // Incomplete code sample
    wxDbTable users;
    .....
    users.SetWhereClause("");

    // This Count() will return 4, as there are four users listed above
    // that match the query parameters
    totalNumberOfUsers = users.Count();

    // This Count() will return 3, as there are only 3 unique first names
    // in the table above - John, Richard, Michael.
    totalNumberOfUniqueFirstNames = users.Count("DISTINCT FIRST_NAME");
\end{verbatim}


\membersection{wxDbTable::CreateIndex}\label{wxdbtablecreateindex}

\func{bool}{CreateIndex}{\param{const char *}{idxName}, \param{bool }{unique}, \param{int }{noIdxCols}, \param{wxDbIdxDef *}{pIdxDefs}, \param{bool }{attemptDrop=TRUE}}

This member function allows you to create secondary (non primary) indexes on 
your tables.  You first create your table, normally specifying a primary 
index, and then create any secondary indexes on the table.  Indexes in 
relational model are not required.  You do not need indexes to look up records 
in a table or to join two tables together.  In the relational model, indexes, 
if available, provide a quicker means to look up data in a table.  To enjoy 
the performance benefits of indexes, the indexes must be defined on the 
appropriate columns and your SQL code must be written in such a way as to 
take advantage of those indexes.

\wxheading{Parameters}

\docparam{idxName}{Name of the Index.  Name must be unique within the table space of the datasource.}
\docparam{unique}{Indicates if this index is unique.}
\docparam{noIdxCols}{Number of columns in the index.}
\docparam{pIdxDefs}{A pointer to an array wxDbIdxDef structures. }
\docparam{attemptDrop}{{\it OPTIONAL}.  Indicates if the function should try 
to execute a \helpref{wxDbTable::DropIndex}{wxdbtabledropindex} on the index 
name provided before trying to create the index name.  Default is TRUE.}

\wxheading{Remarks}

The first parameter, index name, must be unique and should be given a 
meaningful name.  Common practice is to include the table name as a prefix 
in the index name (e.g. PARTS_IDX1).  This will allow you to easily view all 
of the indexes defined for a given table grouped together alphabetically.

The second parameter indicates if the index is unique or not.  Uniqueness 
is enforced at the RDBMS level controlling whether duplicates cannot be 
inserted into the table for unique indices.

In the third parameter, specify how many columns are in your index.  This 
number must match the number of columns defined in the 'pIdxDefs' parameter.

The fourth parameter specifies which columns make up the index using the 
wxDbIdxDef structure.  For each column in the index, you must specify two 
things, the column name and the sort order (ascending / descending).  See 
the example below to see how to build and pass in the wxDbIdxDef structure.

The fifth parameter is provided as many datasources will not automatically 
overwrite existing indexes with the same name.  They require that the 
existing index must be dropped first, so this is the default behavior.

Some datasources (MySQL, and possibly others) require columns which are to be 
part of an index to be defined as NOT NULL.  When this function is called, if 
a column is not defined to be NOT NULL, this function will modify the column 
definition to change the column to be NOT NULL.

PostGres is unable to handle index definitions which specify whether the index 
is ascending or descending, and defaults to the system default when the index 
is created.

It is not necessary to call \helpref{wxDb::CommitTrans}{wxdbcommittrans} 
after executing this function.

\wxheading{Example}

\begin{verbatim}
    // Create a secondary index on the PARTS table
    wxDbIdxDef  idxDef[2];  // 2 columns make up the index

    strcpy(idxDef[0].ColName, "PART_DESC");  // Column 1
    idxDef[0].Ascending = TRUE;

    strcpy(idxDef[1].ColName, "SERIAL_NO");  // Column 2
    idxDef[1].Ascending = FALSE;

    // Create a name for the index based on the table's name
    wxString indexName;
    indexName.sprintf("%s_IDX1",parts->GetTableName());
    parts->CreateIndex(indexName.c_str(), TRUE, 2, idxDef);
\end{verbatim}


\membersection{wxDbTable::CreateTable}\label{wxdbtablecreatetable}

\func{bool}{CreateTable}{\param{bool }{attemptDrop=TRUE}}

Creates a table based on the definitions previously defined for this
wxDbTable instance.

\wxheading{Parameters}

\docparam{attemptDrop}{{\it OPTIONAL}.  Default is TRUE.}

\wxheading{Remarks}

This function creates the table and primary index (if any) in the table space 
associated with the connected data source.  The owner of these objects will 
be the user id that was given when \helpref{wxDb::Open}{wxdbopen} was called.  The objects will 
be created in the default schema for that user.

In your derived wxDbTable object constructor, the columns and primary index 
of the table are described through the wxDbColDef structure.  
\helpref{wxDbTable::CreateTable}{wxdbtablecreatetable} uses this information to create the table and to add 
the primary index.  See \helpref{wxDbTable}{wxdbtable} ctor and wxDbColDef 
description for additional information on describing the columns of the table.

It is not necessary to call \helpref{wxDb::CommitTrans}{wxdbcommittrans} 
after executing this function.


\membersection{wxDbTable::DB_STATUS}\label{wxdbtabledbstatus}

\func{bool}{DB_STATUS}{\void}

Accessor function that returns the wxDb private member variable DB_STATUS for 
the database connection used by this instance of wxDbTable.


\membersection{wxDbTable::Delete}\label{wxdbtabledelete}

\func{bool}{Delete}{\void}

Deletes the current record from the data source.

\wxheading{Remarks}

Use \helpref{wxDbTable::GetFirst}{wxdbtablegetfirst}, \helpref{wxDbTable::GetLast}{wxdbtablegetlast}, 
\helpref{wxDbTable::GetNext}{wxdbtablegetnext} or
\helpref{wxDbTable::GetPrev}{wxdbtablegetprev} to position the cursor to 
a valid record.  Once positioned on a record, call this function to delete 
the row from the table.

A \helpref{wxDb::CommitTrans}{wxdbcommittrans} or 
\helpref{wxDb::RollbackTrans}{wxdbrollbacktrans} must be called after use of 
this function to commit or rollback the deletion.

NOTE: Most datasources have a limited size "rollback" segment.  This means 
that it is only possible to insert/update/delete a finite number of rows 
without performing a \helpref{wxDb::CommitTrans}{wxdbcommittrans} or 
\helpref{wxDb::RollbackTrans}{wxdbrollbacktrans}.  Size of the rollback 
segment varies from database to database, and is user configurable in 
most databases.  Therefore it is usually best to try to perform a commit 
or rollback at relatively small intervals when processing a larger number 
of actions that insert/update/delete rows in a table.


\membersection{wxDbTable::DeleteCursor}\label{wxdbtabledeletecursor}

\func{bool}{DeleteCursor}{\param{HSTMT *}{hstmtDel}}

Allows a program to delete a cursor.

\wxheading{Parameters}

\docparam{hstmtDel}{Handle of the cursor to delete.}

\wxheading{Remarks}

For default cursors associated with the instance of wxDbTable, it is not 
necessary to specifically delete the cursors.  This is automatically done 
in the wxDbTable destructor.

NOTE: If the cursor could not be deleted for some reason, an error is logged 
indicating the reason.  Even if the cursor could not be deleted, the HSTMT 
that is passed in is deleted, and the pointer is set to NULL.


\membersection{wxDbTable::DeleteMatching}\label{wxdbtabledeletematching}

\func{bool}{DeleteMatching}{\void}

This member function allows you to delete records from your wxDbTable object 
by specifying the data to match in the columns to match on.  

\wxheading{Remarks}

To delete all users with a first name of "JOHN", do the following:

\begin{verbatim}
    1)  Clear all "columns" using \helpref{wxDbTable::ClearMemberVars}{wxdbtableclearmembervars}.
    2)  Set the FIRST_NAME column equal to "JOHN".
    3)  Call \helpref{wxDbTable::DeleteMatching}{wxdbtabledeletematching}.
\end{verbatim}

The WHERE clause is built by the ODBC class library based on all non-zero 
columns.  This allows deletion of records by matching on any column(s) 
in your wxDbTable instance, without having to write the SQL WHERE clause.

A \helpref{wxDb::CommitTrans}{wxdbcommittrans} or 
\helpref{wxDb::RollbackTrans}{wxdbrollbacktrans} must be called after use of 
this function to commit or rollback the deletion.

NOTE: Row(s) should be locked before deleting them to make sure they are 
not already in use.  This can be achieved by calling \helpref{wxDbTable::QueryMatching}{wxdbtablequerymatching}, 
and then scrolling through the records locking each as you go.  After the 
row(s) have been successfully locked, call this function.

NOTE: Most datasources have a limited size "rollback" segment.  This means 
that it is only possible to insert/update/delete a finite number of rows 
without performing a \helpref{wxDb::CommitTrans}{wxdbcommittrans} or 
\helpref{wxDb::RollbackTrans}{wxdbrollbacktrans}.  Size of the rollback 
segment varies from database to database, and is user configurable in 
most databases.  Therefore it is usually best to try to perform a commit 
or rollback at relatively small intervals when processing a larger number 
of actions that insert/update/delete rows in a table.


\wxheading{Example}

\begin{verbatim}
    // Incomplete code sample to delete all users with a first name
    // of "JOHN"
    users.ClearMemberVars();
    strcpy(users.FirstName,"JOHN");
    users.DeleteMatching();
\end{verbatim}


\membersection{wxDbTable::DeleteWhere}\label{wxdbtabledeletewhere}

\func{bool}{DeleteWhere}{\param{const char *}{pWhereClause}}

Deletes all rows from the table which match the criteria specified in the 
WHERE clause that is passed in as the sole parameter.

\wxheading{Parameters}

\docparam{pWhereClause}{SQL WHERE clause.  This WHERE clause determines which 
records will be deleted from the table interfaced through the wxDbTable 
instance.  The WHERE clause passed in must be compliant with the SQL 92 
grammar.  Do not include the keyword 'WHERE'
}

\wxheading{Remarks}

This is the most powerful form of the wxDbTable delete functions.  This 
function gives access to the full power of SQL.  This function can be used 
to delete records by passing a valid SQL WHERE clause.  Sophisticated 
deletions can be performed based on multiple criteria using the full 
functionality of the SQL language.  

A \helpref{wxDb::CommitTrans}{wxdbcommittrans} must be called after use of 
this function to commit the deletions.

Note: This function is limited to deleting records from the table associated 
with this wxDbTable object only.  Deletions on joined tables is not possible.

NOTE: Most datasources have a limited size "rollback" segment.  This means 
that it is only possible to insert/update/delete a finite number of rows 
without performing a \helpref{wxDb::CommitTrans}{wxdbcommittrans} or 
\helpref{wxDb::RollbackTrans}{wxdbrollbacktrans}.  Size of the rollback 
segment varies from database to database, and is user configurable in 
most databases.  Therefore it is usually best to try to perform a commit 
or rollback at relatively small intervals when processing a larger number 
of actions that insert/update/delete rows in a table.

\wxheading{Example}

\begin{verbatim}
    // Delete parts 1 thru 10 from containers 'X', 'Y' and 'Z' that 
    // are magenta in color
    parts.DeleteWhere("(PART_NUMBER BETWEEN 1 AND 10) AND \
                        CONTAINER IN ('X', 'Y', 'Z') AND \
                        UPPER(COLOR) = 'MAGENTA'");
\end{verbatim}


\membersection{wxDbTable::DropIndex}\label{wxdbtabledropindex}

\func{bool}{DropIndex}{\param{const char *}{idxName}}

Allows an index on the associated table to be dropped (deleted) if the user 
login has sufficient privileges to do so.

\wxheading{Parameters}

\docparam{idxName}{Name of the index to be dropped.}

\wxheading{Remarks}

If the index specified in the 'idxName' parameter does not exist, an error 
will be logged, and the function will return a result of FALSE.

It is not necessary to call \helpref{wxDb::CommitTrans}{wxdbcommittrans} 
after executing this function.


\membersection{wxDbTable::DropTable}\label{wxdbtabledroptable}

\func{bool}{DropTable}{\void}

Deletes the associated table if the user has sufficient privileges to do so.

\wxheading{Remarks}

This function returns TRUE if the table does not exist, but only for 
supported databases (see \helpref{wxDb::Dbms}{wxdbdbms}).  If a datasource 
is not specifically supported, and this function is called, the function 
will return FALSE.

Some datasources/ODBC drivers will delete any indexes associated with the 
table automatically, and others may not.  Check the documentation for your 
database to determine the behavior.

It is not necessary to call \helpref{wxDb::CommitTrans}{wxdbcommittrans} 
after executing this function.


\membersection{wxDbTable::From}\label{wxdbtablefrom}

\func{const char *}{From}{}
\func{void}{From}{\param{const wxString &}{From}}

Accessor function for the private class member wxDbTable::from.  Can be used 
as a synonym for \helpref{wxDbTable::GetFromClause}{wxdbtablegetfromclause} 
(the first form of this function) or  
\helpref{wxDbTable::SetFromClause}{wxdbtablesetfromclause} (the second form 
of this function).

\wxheading{Parameters}

\docparam{From}{A comma separated list of table names that are to be outer 
joined with the base table's columns so that the joined table's columns 
may be returned in the result set or used as a portion of a comparison with 
the base table's columns.  NOTE that the base tables name must NOT be included 
in the FROM clause, as it is automatically included by the wxDbTable class 
in constructing query statements.}

\wxheading{Return value}

The first form of this function returns the current value of the wxDbTable 
member variable ::from.  

The second form of the function has no return value.

\wxheading{See also}

\helpref{wxDbTable::GetFromClause}{wxdbtablegetfromclause}, 
\helpref{wxDbTable::SetFromClause}{wxdbtablesetfromclause}


\membersection{wxDbTable::GetColDefs}\label{wxdbtablegetcoldefs}

\func{wxDbColDef *}{GetColDefs}{}

Accessor function that returns a pointer to the array of column definitions 
that are bound to the columns that this wxDbTable instance is associated 
with.

To determine the number of elements pointed to by the returned 
\helpref{wxDbColDef}{wxdbcoldef} pointer, use the 
\helpref{wxDbTable::GetNumberOfColumns}{wxdbtablegetnumberofcolumns} function.

\wxheading{Remarks}

These column definitions must not be manually redefined after they have been 
set.


\membersection{wxDbTable::GetCursor}\label{wxdbtablegetcursor}

\func{HSTMT}{GetCursor}{\void}

Returns the HSTMT value of the current cursor for this wxDbTable object.  

\wxheading{Remarks}

This function is typically used just before changing to use a different cursor 
so that after the program is finished using the other cursor, the current 
cursor can be set back to being the cursor in use.

\wxheading{See also}

\helpref{wxDbTable::SetCursor}{wxdbtablesetcursor}, \helpref{wxDbTable::GetNewCursor}{wxdbtablegetnewcursor}


\membersection{wxDbTable::GetDb}\label{wxdbtablegetdb}

\func{wxDb *}{GetDb}{}

Accessor function for the private member variable pDb which is a pointer to 
the datasource connection that this wxDbTable instance uses.


\membersection{wxDbTable::GetFirst}\label{wxdbtablegetfirst}

\func{bool}{GetFirst}{\void}

Retrieves the FIRST row in the record set as defined by the current query.  
Before retrieving records, a query must be performed using 
\helpref{wxDbTable::Query}{wxdbtablequery}, 
\helpref{wxDbTable::QueryOnKeyFields}{wxdbtablequeryonkeyfields}, 
\helpref{wxDbTable::QueryMatching}{wxdbtablequerymatching} or 
\helpref{wxDbTable::QueryBySqlStmt}{wxdbtablequerybysqlstmt}.

\wxheading{Remarks}

This function can only be used if the datasource connection used by the 
wxDbTable instance was created with FwdOnlyCursors set to FALSE.  If the 
connection does not allow backward scrolling cursors, this function will 
return FALSE, and the data contained in the bound columns will be undefined.

\wxheading{See also}

\helpref{wxDb::FwdOnlyCursors}{wxdbfwdonlycursors}


\membersection{wxDbTable::GetFromClause}\label{wxdbtablegetfromclause}

\func{const char *}{GetFromClause}{}

Accessor function that returns the current FROM setting assigned with the 
\helpref{wxDbTable::SetFromClause}{wxdbtablesetfromclause}.

\wxheading{See also}

\helpref{wxDbTable::From}{wxdbtablefrom}


\membersection{wxDbTable::GetLast}\label{wxdbtablegetlast}

\func{bool}{GetLast}{\void}

Retrieves the LAST row in the record set as defined by the current query.  
Before retrieving records, a query must be performed using 
\helpref{wxDbTable::Query}{wxdbtablequery}, 
\helpref{wxDbTable::QueryOnKeyFields}{wxdbtablequeryonkeyfields}, 
\helpref{wxDbTable::QueryMatching}{wxdbtablequerymatching} or 
\helpref{wxDbTable::QueryBySqlStmt}{wxdbtablequerybysqlstmt}.

\wxheading{Remarks}

This function can only be used if the datasource connection used by the 
wxDbTable instance was created with FwdOnlyCursors set to FALSE.  If the 
connection does not allow backward scrolling cursors, this function will 
return FALSE, and the data contained in the bound columns will be undefined.

\wxheading{See also}

\helpref{wxDb::FwdOnlyCursors}{wxdbfwdonlycursors}


\membersection{wxDbTable::GetNewCursor}\label{wxdbtablegetnewcursor}

\func{HSTMT *}{GetNewCursor}{\param{bool }{setCursor=FALSE}, \param{bool }{bindColumns=TRUE}}

\begin{comment}
% George: @@@@@@@@STILL TO DO
\end{comment}

\wxheading{Parameters}

\docparam{setCursor}{{\it OPTIONAL}.  Default is FALSE.}
\docparam{bindColumns}{{\it OPTIONAL}.  Default is TRUE.}

\wxheading{Remarks}


\membersection{wxDbTable::GetNext}\label{wxdbtablegetnext}

\func{bool}{GetNext}{\void}

Retrieves the NEXT row in the record set after the current cursor position 
as defined by the current query.  Before retrieving records, a query must be 
performed using \helpref{wxDbTable::Query}{wxdbtablequery}, 
\helpref{wxDbTable::QueryOnKeyFields}{wxdbtablequeryonkeyfields}, 
\helpref{wxDbTable::QueryMatching}{wxdbtablequerymatching} or 
\helpref{wxDbTable::QueryBySqlStmt}{wxdbtablequerybysqlstmt}.

\wxheading{Return value}

This function returns FALSE when the current cursor has reached the end of 
the result set.  When FALSE is returned, data in the bound columns is 
undefined.

\wxheading{See also}
\helpref{wxDbTable::++}{wxdbtableplusplus}


\membersection{wxDbTable::GetNumberOfColumns}\label{wxdbtablegetnumberofcolumns}

\func{bool}{GetNumberOfColumns}{}

Accessor function that returns the number of columns that are statically 
bound for access by the wxDbTable instance.


\membersection{wxDbTable::GetOrderByClause}\label{wxdbtablegetorderbyclause}

\func{const char *}{GetOrderByClause}{}

Accessor function that returns the current ORDER BY setting assigned with 
the \helpref{wxDbTable::SetOrderByClause}{wxdbtablesetorderbyclause}.

\wxheading{See also}

\helpref{wxDbTable::OrderBy}{wxdbtableorderby}


\membersection{wxDbTable::GetPrev}\label{wxdbtablegetprev}

\func{bool}{GetPrev}{\void}

Retrieves the PREVIOUS row in the record set before the current cursor 
position as defined by the current query.  Before retrieving records, a 
query must be performed using \helpref{wxDbTable::Query}{wxdbtablequery}, 
\helpref{wxDbTable::QueryOnKeyFields}{wxdbtablequeryonkeyfields}, 
\helpref{wxDbTable::QueryMatching}{wxdbtablequerymatching} or 
\helpref{wxDbTable::QueryBySqlStmt}{wxdbtablequerybysqlstmt}.

\wxheading{Return value}

This function returns FALSE when the current cursor has reached the beginning 
of the result set and there are now other rows prior to the cursors current 
position.  When FALSE is returned, data in the bound columns is undefined.

\wxheading{Remarks}

This function can only be used if the datasource connection used by the 
wxDbTable instance was created with FwdOnlyCursors set to FALSE.  If the 
connection does not allow backward scrolling cursors, this function will 
return FALSE, and the data contained in the bound columns will be undefined.

\wxheading{See also}

\helpref{wxDb::FwdOnlyCursors}{wxdbfwdonlycursors}, 
\helpref{wxDbTable::--}{wxdbtableminusminus}


\membersection{wxDbTable::GetQueryTableName}\label{wxdbtablegetquerytablename}

\func{const char *}{GetQueryTableName}{}

Accessor function that returns the name of the table/view that was indicated 
as being the table/view to query against when this wxDbTable instance was 
created.

\wxheading{See also}

\helpref{wxDbTable constructor}{wxdbtableconstr}


\membersection{wxDbTable::GetRowNum}\label{wxdbtablegetrownum}

\func{UWORD}{GetRowNum}{\void}

Returns the ODBC row number for performing positioned updates and deletes.  

\wxheading{Remarks}

This function is not being used within the ODBC class library and may be a 
candidate for removal if no use is found for it.


\membersection{wxDbTable::GetTableName}\label{wxdbtablegettablename}

\func{const char *}{GetTableName}{}

Accessor function that returns the name of the table that was indicated 
as being the table that this wxDbTable instance was associated with.


\membersection{wxDbTable::GetTablePath}\label{wxdbtablegettablepath}

\func{const char *}{GetTablePath}{}

Accessor function that returns the path to the data table that was indicated 
during creation of this wxDbTable instance.

\wxheading{Remarks}

Currently only applicable to dBase and MS-Access datasources.


\membersection{wxDbTable::GetWhereClause}\label{wxdbtablegetwhereclause}

\func{const char *}{GetWhereClause}{}

Accessor function that returns the current WHERE setting assigned with the 
\helpref{wxDbTable::SetWhereClause}{wxdbtablesetwhereclause}

\wxheading{See also}

\helpref{wxDbTable::Where}{wxdbtablewhere}


\membersection{wxDbTable::Insert}\label{wxdbtableinsert}

\func{int}{Insert}{\void}

Inserts a new record into the table being referenced by this wxDbTable 
instance.  The values in the member variables of the wxDbTable instance are 
inserted into the columns of the new row in the database
 
\wxheading{Return value}

\begin{verbatim}
    DB_SUCCESS              Record inserted successfully (value = 1)

    DB_FAILURE              Insert failed (value = 0)

    DB_ERR_INTEGRITY_CONSTRAINT_VIOL    
                            The insert failed due to an integrity
                            constraint violation (duplicate non-unique
                            index entry) is attempted.
\end{verbatim}

\wxheading{Remarks}

A \helpref{wxDb::CommitTrans}{wxdbcommittrans} or 
\helpref{wxDb::RollbackTrans}{wxdbrollbacktrans} must be called after use of 
this function to commit or rollback the insertion.

\wxheading{Example}

\begin{verbatim}
    // Incomplete code snippet
    strcpy(parts->PartName, "10");
    strcpy(parts->PartDesc, "Part #10");
    parts->Qty = 1000;
    RETCODE retcode = parts.Insert();
    switch(retcode)
    {
        case DB_SUCCESS:
            parts->GetDb()->CommitTrans();
            return(TRUE);
        case DB_ERR_INTEGRITY_CONSTRAINT_VIOL:
            // Current data would result in a duplicate key
            // on one or more indexes that do not allow duplicates
            parts->GetDb()->RollbackTrans();
            return(FALSE);
        default:
            // Insert failed for some unexpected reason
            parts->GetDb()->RollbackTrans();
            return(FALSE);
    }
\end{verbatim}


\membersection{wxDbTable::IsColNull}\label{wxdbtableiscolnull}

\func{bool}{IsColNull}{\param{int }{colNo}}

Used primarily in the ODBC class library to determine if a column is equal 
to "NULL".  Works for all data types supported by the ODBC class library.

\wxheading{Parameters}

\docparam{colNo}{The column number of the bound column as defined by the 
\helpref{wxDbTable::SetColDefs}{wxdbtablesetcoldefs}
calls which defined the columns accesible to this wxDbTable instance.}

\wxheading{Remarks}

NULL column support is currently not fully implemented as of wxWindows 2.4


\membersection{wxDbTable::IsCursorClosedOnCommit}\label{wxdbtableiscursorclosedoncommit}

\func{bool}{IsCursorClosedOnCommit}{\void}

Accessor function to return information collected during the opening of the 
datasource connection that is used by this wxDbTable instance.

\wxheading{Return value}

Returns TRUE if the cursor associated with this wxDbTable object is closed 
after a commit or rollback operation.  Returns FALSE otherwise.


\membersection{wxDbTable::IsQueryOnly}\label{wxdbtableisqueryonly}

\func{bool}{IsQueryOnly}{}

Accessor function that returns a value indicating if this wxDbTable instance 
was created to allow only queries to be performed on the bound columns.  If 
this function returns TRUE, then no actions may be performed using this 
wxDbTable instance that would modify (insert/delete/update) the table's data.


\membersection{wxDbTable::Open}\label{wxdbtableopen}

\func{bool}{Open}{\void}

Every wxDbTable instance must be opened before it can be used.  This function 
checks for the existence of the requested table, binds columns to the 
internal cursors needed (insert/update/select) and constructs the insert 
statement that is used for inserting data to the columns of a new row in 
the datasource.

\wxheading{Remarks}

If the function returns a FALSE value due to the table not existing, a log 
entry is recorded for the datasource connection indicating the problem 
that was detected when checking for table existence.  Note that it is usually 
best for the calling routine to check for the existence of the table and for 
sufficent user privileges to access the table in the mode (wxDB_QUERY_ONLY or 
!wxDB_QUERY_ONLY) before trying to open the table for the best possible 
return results as to why a table cannot be opened.

\wxheading{See also}

\helpref{wxDb::TableExists}{wxdbtableexists}, \helpref{wxDb::TablePrivileges}{wxdbtableprivileges}


\membersection{wxDbTable::OrderBy}\label{wxdbtableorderby}

\func{const char *}{OrderBy}{}
\func{void}{OrderBy}{\param{const wxString &}{OrderBy}}

Accessor function for the private class member wxDbTable::orderBy.  Can be 
used as a synonym for \helpref{wxDbTable::GetOrderByClause}{wxdbtablegetorderbyclause} 
(the first form of this function) or \helpref{wxDbTable::SetOrderByClause}{wxdbtablesetorderbyclause} 
(the second form of this function).

\wxheading{Parameters}

\docparam{OrderBy}{A comma separated list of column names that indicate the 
alphabetized sorting sequence that the result set is to be returned in.  If 
a FROM clause has also been specified, each column name specified in the 
ORDER BY clause should be prefaced with the table name to which the column 
belongs using DOT notation (TABLE.COLUMN).}

\wxheading{Return value}

The first form of this function returns the current value of the wxDbTable 
member variable ::orderBy.  

The second form of the function has no return value.

\wxheading{See also}

\helpref{wxDbTable::GetOrderByClause}{wxdbtablegetorderbyclause}, 
\helpref{wxDbTable::SetFromClause}{wxdbtablesetfromclause}


\membersection{wxDbTable::Query}\label{wxdbtablequery}

\func{virtual bool}{Query}{\param{bool }{forUpdate=FALSE}, \param{bool }{distinct=FALSE}}

\wxheading{Parameters}

\docparam{forUpdate}{{\it OPTIONAL}.  Gives you the option of locking records 
as they are queried (SELECT ... FOR UPDATE).  If the RDBMS is not capable of 
the FOR UPDATE clause, this argument is ignored.  See 
\helpref{wxDbTable::CanSelectForUpdate}{wxdbtablecanselectforupdate} for 
additional information regarding this argument.  Default is FALSE.}
\docparam{distinct}{{\it OPTIONAL}.  Allows selection of only distinct values 
from the query (SELECT DISTINCT ... FROM ...).  The notion of DISTINCT 
applies to all columns returned in the result set, not individual columns.  
Default is FALSE.}

\wxheading{Remarks}

This function queries records from the datasource based on the three  
wxDbTable members: "where", "orderBy", and "from".  Use 
\helpref{wxDbTable::SetWhereClause}{wxdbtablesetwhereclause} to filter on 
records to be retrieved (e.g. All users with a first name of "JOHN").  
Use \helpref{wxDbTable::SetOrderByClause}{wxdbtablesetorderbyclause} to 
change the sequence in which records are returned in the result set from 
the datasource (e.g. Ordered by LAST_NAME).  Use 
\helpref{wxDbTable::SetFromClause}{wxdbtablesetfromclause} to allow outer 
joining of the base table (the one being associated with this instance of 
wxDbTable) with other tables which share a related field.  

After each of these clauses are set/cleared, call wxDbTable::Query() to 
fetch the result set from the datasource.  

This scheme has an advantage if you have to requery your record set 
frequently in that you only have to set your WHERE, ORDER BY, and FROM 
clauses once.  Then to refresh the record set, simply call wxDbTable::Query() 
as frequently as needed.  

Note that repeated calls to wxDbTable::Query() may tax the database 
server and make your application sluggish if done too frequently or 
unnecessarily.  

The base table name is automatically prepended to the base column names in 
the event that the FROM clause has been set (is non-null) using 
\helpref{wxDbTable::SetFromClause}{wxdbtablesetfromclause}.

The cursor for the result set is positioned {\it before} the first record in 
the record set after the query.  To retrieve the first record, call 
\helpref{wxDbTable::GetFirst}{wxdbtablegetfirst} or 
\helpref{wxDbTable::GetNext}{wxdbtablegetnext}.  Typically, no data from the 
result set is returned to the client driver until a request to such as 
\helpref{wxDbTable::GetNext}{wxdbtablegetnext} is performed, so network 
traffic and database load are not overwhelmed transmitting data until the 
data is actually requested by the client.  This behavior is solely dependent 
on the ODBC driver though, so refer to the ODBC driver's reference material 
for information on its behaviors.

The wxDbTable::Query() function is defined as "virtual" so that it may be 
overridden for application specific purposes.

\normalbox{Be sure and set the wxDbTable's "where", "orderBy", and "from" 
member variables to "" if they are not being used in the query.  Otherwise, 
the results returned may have unexpected results (or no results) due to 
improper or incorrect query parameters constructed from the uninitialized 
clauses.}

\wxheading{Example}

\begin{verbatim}
    // Incomplete code sample
    parts->SetWhereClause("DESCRIPTION = 'FOOD'");
    parts->SetOrderByClause("EXPIRATION_DATE");
    parts->SetFromClause("");
    // Query the records based on the where, orderBy and from clauses 
    // specified above
    parts->Query();
    // Display all records queried
    while(parts->GetNext())
        dispPart(parts);  // user defined function
\end{verbatim}


\membersection{wxDbTable::QueryBySqlStmt}\label{wxdbtablequerybysqlstmt}

\func{bool}{QueryBySqlStmt}{\param{const char *}{pSqlStmt}}

Performs a query against the datasource by accepting and passing verbatim the 
SQL SELECT statement passed to the function.

\wxheading{Parameters}

\docparam{pSqlStmt}{A pointer to the SQL SELECT statement to be executed.}

\wxheading{Remarks}

This is the most powerful form of the query functions available.  This member 
function allows a programmer to write their own custom SQL SELECT statement 
for requesting data from the data source.  This gives the programmer access 
to the full power of SQL for performing operations such as scalar functions, 
aggregate functions, table joins, and sub-queries, as well as datasource 
specific function calls.  

The requirements of the SELECT statement are the following:

\begin{verbatim}
    1. Must return the correct number of columns.  In the derived wxDbTable 
       constructor, it is specified how many columns are in the wxDbTable 
       object.  The SELECT statement must return exactly that many columns.

    2. The columns must be returned in the same sequence as specified 
       when defining the bounds columns using wxDbTable::SetColDefs(), and 
       the columns returned must be of the proper data type.  For example, 
       if column 3 is defined in the wxDbTable bound column definitions to be a float, 
       the SELECT statement must return a float for column 3 (e.g. 
       PRICE * 1.10 to increase the price by 10%).

    3. The ROWID can be included in your SELECT statement as the last column 
       selected, if the datasource supports it.  Use wxDbTable::CanUpdByROWID() 
       to determine if the ROWID can be selected from the datasource.  If it 
       can, much better performance can be achieved on updates and deletes 
       by including the ROWID in the SELECT statement.
\end{verbatim}

Even though data can be selected from multiple tables in your select 
statement (joins), only the base table associated with this wxDbTable object
is automatically updated through the ODBC class library.  Data from multiple 
tables can be selected for display purposes however.  Include columns in 
the wxDbTable object and mark them as non-updateable (See 
\helpref{wxDbColDef}{wxdbcoldef} for details).  This way columns can be 
selected and displayed from other tables, but only the base table will be 
updated automatically through the \helpref{wxDbTable::Update}{wxdbtableupdate} 
function.  To update tables other than the base table, use the 
\helpref{wxDbTable::Update}{wxdbtableupdate} function passing a SQL statement.

After this function has been called, the cursor is positioned before the 
first record in the record set.  To retrieve the first record, call 
either \helpref{wxDbTable::GetFirst}{wxdbtablegetfirst} or 
\helpref{wxDbTable::GetNext}{wxdbtablegetnext}.

\wxheading{Example}

\begin{verbatim}
    // Incomplete code samples
    strcpy(sqlStmt, "SELECT * FROM PARTS WHERE STORAGE_DEVICE = 'SD98' \
                     AND CONTAINER = 12");
    // Query the records using the SQL SELECT statement above
    parts->QueryBySqlStmt(sqlStmt);
    // Display all records queried
    while(parts->GetNext())
        dispPart(&parts);

    Example SQL statements
    ----------------------

    // Table Join returning 3 columns
    SELECT part_no, part_desc, sd_name
        from parts, storage_devices
        where parts.storage_device_id = storage_devices.storage_device_id

    // Aggregate function returning total number of parts in container 99
    SELECT count(*) from PARTS where container = 99

    // Order by clause; ROWID, scalar function
    SELECT part_no, substring(part_desc, 1, 10), qty_on_hand + 1, ROWID
        from parts
        where warehouse = 10
        order by part_no desc           // descending order

    // Subquery
    SELECT * from parts
        where container in (select container
        from storage_devices
            where device_id = 12)
\end{verbatim}


\membersection{wxDbTable::QueryMatching}\label{wxdbtablequerymatching}

\func{virtual bool}{QueryMatching}{\param{bool }{forUpdate=FALSE}, \param{bool }{distinct=FALSE}}

QueryMatching allows querying of records from the table associated with 
the wxDbTable object by matching "columns" to values.  

For example: To query the datasource for the row with a PART_NUMBER column 
value of "32", clear all column variables of the wxDbTable object, set the 
PartNumber variable that is bound to the PART_NUMBER column in the wxDbTable 
object to "32", and then call wxDbTable::QueryMatching().

\wxheading{Parameters}

\docparam{forUpdate}{{\it OPTIONAL}.  Gives you the option of locking records 
as they are queried (SELECT ... FOR UPDATE).  If the RDBMS is not capable of 
the FOR UPDATE clause, this argument is ignored.  See 
\helpref{wxDbTable::CanSelectForUpdate}{wxdbtablecanselectforupdate} for 
additional information regarding this argument.  Default is FALSE.}
\docparam{distinct}{{\it OPTIONAL}.  Allows selection of only distinct values 
from the query (SELECT DISTINCT ... FROM ...).  The notion of DISTINCT 
applies to all columns returned in the result set, not individual columns.  
Default is FALSE.}

\wxheading{Remarks}

The SQL WHERE clause is built by the ODBC class library based on all 
non-zero/non-NULL columns in your wxDbTable object.  Matches can be on one, 
many or all of the wxDbTable's columns.  The base table name is prepended 
to the column names in the event that the wxDbTable's FROM clause is non-null.

This function cannot be used to perform queries which will check for 
columns that are 0 or NULL, as the automatically constructed WHERE clause 
only will contain comparisons on column member variables that are 
non-zero/non-NULL.

The primary difference between this function and \helpref{wxDbTable::QueryOnKeyFields}{wxdbtablequeryonkeyfields} 
is that this function can query on any column(s) in the wxDbTable object.  
Note however that this may not always be very efficient.  Searching on 
non-indexed columns will always require a full table scan.

The cursor is positioned before the first record in the record set after 
the query is performed.  To retrieve the first record, the program must call 
either \helpref{wxDbTable::GetFirst}{wxdbtablegetfirst} or 
\helpref{wxDbTable::GetNext}{wxdbtablegetnext}.

\wxheading{Example}

\begin{verbatim}
    // Incomplete code sample
    parts->ClearMemberVars();           // Set all columns to zero
    strcpy(parts->PartNumber,"32");     // Set columns to query on
    parts->OnHold = TRUE;
    parts->QueryMatching();             // Query
    // Display all records queried
    while(parts->GetNext())
        dispPart(parts);  // Some application defined function
\end{verbatim}


\membersection{wxDbTable::QueryOnKeyFields}\label{wxdbtablequeryonkeyfields}

\func{bool}{QueryOnKeyFields}{\param{bool }{forUpdate=FALSE}, \param{bool }{distinct=FALSE}}

QueryOnKeyFields provides an easy mechanism to query records in the table 
associated with the wxDbTable object by the primary index column(s).  Simply 
assign the primary index column(s) values and then call this member function 
to retrieve the record.  

Note that since primary indexes are always unique, this function implicitly 
always returns a single record from the database. The base table name is 
prepended to the column names in the event that the wxDbTable's FROM clause 
is non-null.

\wxheading{Parameters}

\docparam{forUpdate}{{\it OPTIONAL}.  Gives you the option of locking records 
as they are queried (SELECT ... FOR UPDATE).  If the RDBMS is not capable of 
the FOR UPDATE clause, this argument is ignored.  See 
\helpref{wxDbTable::CanSelectForUpdate}{wxdbtablecanselectforupdate} for 
additional information regarding this argument.  Default is FALSE.}
\docparam{distinct}{{\it OPTIONAL}.  Allows selection of only distinct values 
from the query (SELECT DISTINCT ... FROM ...).  The notion of DISTINCT 
applies to all columns returned in the result set, not individual columns.  
Default is FALSE.}

\wxheading{Remarks}

The cursor is positioned before the first record in the record set after 
the query is performed.  To retrieve the first record, the program must call 
either \helpref{wxDbTable::GetFirst}{wxdbtablegetfirst} or 
\helpref{wxDbTable::GetNext}{wxdbtablegetnext}.

\wxheading{Example}

\begin{verbatim}
    // Incomplete code sample
    strcpy(parts->PartNumber, "32");
    parts->QueryOnKeyFields();
    // Display all records queried
    while(parts->GetNext())
        dispPart(parts);  // Some application defined function
\end{verbatim}


\membersection{wxDbTable::Refresh}\label{wxdbtablerefresh}

\func{bool}{Refresh}{\void}

Refreshes (re-reads into the bound columns) the current record for the 
current active cursor of the wxDbTable object.  

The cursor position and result set are unaffected by calls to this function.
(The one exception is in the case where the record to be refreshed has been 
deleted by some other user or transaction since it was originally retrieved 
as part of the result set.  For most datasources, the default behavior in 
this situation is to return the value that was originally queried for the 
result set, even though it has been deleted from the database.  But this is 
datasource dependent, and should be tested before relying on this behavior.)

\wxheading{Remarks}

This routine is only guaranteed to work if the table has a unique primary 
index defined for it.  Otherwise, more than one record may be fetched and 
there is no guarantee that the correct record will be refreshed.  The 
table's columns are refreshed to reflect the current data in the database.


\membersection{wxDbTable::SetColDefs}\label{wxdbtablesetcoldefs}

\func{void}{SetColDefs}{\param{int }{index}, \param{const char *}{fieldName}, \param{int }{dataType}, \param{void *}{pData}, \param{int }{cType}, \param{int }{size}, \param{bool }{keyField = FALSE}, \param{bool }{upd = TRUE}, \param{bool }{insAllow = TRUE}, \param{bool }{derivedCol = FALSE}}

\func{wxDbColDataPtr *}{SetColDefs}{\param{wxDbColInf *}{colInfs}, \param{ULONG }{numCols}}

\wxheading{Parameters}

\docparam{index}{Column number (0 to n-1, where n is the number of columns 
specified as being defined for this wxDbTable instance when the 
wxDbTable constructor was called.}
\docparam{fieldName}{Column name from the associated data table.}
\docparam{dataType}{Logical data type.  Valid logical types include:}

\begin{verbatim}
    DB_DATA_TYPE_VARCHAR        : strings
    DB_DATA_TYPE_INTEGER        : non-floating point numbers
    DB_DATA_TYPE_FLOAT          : floating point numbers
    DB_DATA_TYPE_DATE           : dates
\end{verbatim}

\docparam{pData}{Pointer to the data object that will hold the column's 
value when a row of data is returned from the datasource.}
\docparam{cType}{SQL C Type.  This defines the data type that the SQL 
representation of the data is converted to to be stored in {\it pData}.
Other valid types are available also, but these are the most common ones:}

\begin{verbatim}
    SQL_C_CHAR      // strings
    SQL_C_LONG
    SQL_C_ULONG
    SQL_C_SHORT
    SQL_C_USHORT
    SQL_C_FLOAT
    SQL_C_DOUBLE
    SQL_C_NUMERIC   
    SQL_C_TIMESTAMP

    SQL_C_BOOLEAN   // defined in db.h
    SQL_C_ENUM      // defined in db.h
\end{verbatim}

\docparam{size}{Maximum size in bytes of the {\it pData} object.}
\docparam{keyField}{{\it OPTIONAL}.  Indicates if this column is part of the 
primary index.  Default is FALSE.}
\docparam{upd}{{\it OPTIONAL}.  Are updates allowed on this column?  
Default is TRUE.}
\docparam{insAllow}{{\it OPTIONAL}.  Inserts allowed on this column?  
Default is TRUE.}
\docparam{derivedCol}{{\it OPTIONAL}.  Is this a derived column (non base 
table column for query only)?  Default is FALSE.}

\docparam{colInfs}{Pointer to an array of wxDbColInf instances which contains 
all the information necessary to create {\it numCols} column definitions.}
\docparam{numCols}{Number of elements of wxDbColInf type that are pointed 
to by {\it colInfs}, which are to have column definitions created from them.}

\wxheading{Remarks}

If {\it pData} is to hold a string of characters, be sure to include enough 
space for the NULL terminator in pData and in the byte count of {\it size}.

Both forms of this function provide a shortcut for defining the columns in 
your wxDbTable object.  Use this function in any derived wxDbTable 
constructor when describing the column/columns in the wxDbTable object.

The second form of this function is primarily used when the 
\helpref{wxDb::GetColumns}{wxdbgetcolumns} function was used to query the 
datasource for the column definitions, so that the column definitions are 
already stored in wxDbColInf form.  One example use of using 
\helpref{wxDb::GetColumns}{wxdbgetcolumns} then using this function is if 
a data table existed in one datasource, and the table's column definitions 
were to be copied over to another datasource or table.

\wxheading{Example}

\begin{verbatim}
    // Long way not using this function
    strcpy(colDefs[0].ColName, "PART_NO");
    colDefs[0].DbDataType   = DB_DATA_TYPE_VARCHAR;
    colDefs[0].PtrDataObj   = PartNumber;
    colDefs[0].SqlCtype     = SQL_C_CHAR;
    colDefs[0].SzDataObj    = PART_NUMBER_LEN;
    colDefs[0].KeyField     = TRUE;
    colDefs[0].Updateable   = FALSE;
    colDefs[0].InsertAllowed= TRUE;
    colDefs[0].DerivedCol   = FALSE;

    // Shortcut using this function
    SetColDefs(0, "PART_NUMBER", DB_DATA_TYPE_VARCHAR, PartNumber,
               SQL_C_CHAR, PART_NUMBER_LEN, TRUE, FALSE,TRUE,FALSE);
\end{verbatim}


\membersection{wxDbTable::SetCursor}\label{wxdbtablesetcursor}

\func{bool}{Open}{\param{HSTMT *}{hstmtActivate = (void **) wxDB_DEFAULT_CURSOR}}

\wxheading{Parameters}

\docparam{hstmtActivate}{{\it OPTIONAL}.  Pointer to the cursor that is to 
become the current cursor.  Passing no cursor handle will reset the cursor 
back to the wxDbTable's default (original) cursor that was created when the 
wxDbTable instance was first created.  Default is wxDB_DEFAULT_CURSOR.}

\wxheading{Remarks}

When swapping between cursors, the member variables of the wxDbTable object 
are automatically refreshed with the column values of the row that the 
current cursor is positioned at (if any).  If the cursor is not positioned, 
then the data in member variables is undefined.

The only way to return back to the cursor that was in use before this 
function was called is to programmatically determine the current cursor 
BEFORE calling this function using \helpref{wxDbTable::GetCursor}{wxdbtablegetcursor} 
and saving a pointer to that cursor.

\wxheading{See also}

\helpref{wxDbTable::GetNewCursor}{wxdbtablegetnewcursor}, \helpref{wxDbTable::GetCursor}{wxdbtablegetcursor}, 
\helpref{wxDbTable::SetCursor}{wxdbtablesetcursor}


\membersection{wxDbTable::SetFromClause}\label{wxdbtablesetfromclause}

\func{void}{SetFromClause}{\param{const wxString &}{From}}

Accessor function for setting the private class member wxDbTable::from 
that indicates what other tables should be outer joined with the wxDbTable's
base table for access to the columns in those other tables. 

Synonym to this function is one form of \helpref{wxDbTable::From}{wxdbtablefrom}

\wxheading{Parameters}

\docparam{From}{A comma separated list of table names that are to be outer 
joined with the base table's columns so that the joined table's columns 
may be returned in the result set or used as a portion of a comparison with 
the base table's columns.  NOTE that the base tables name must NOT be included 
in the FROM clause, as it is automatically included by the wxDbTable class 
in constructing query statements.}

\wxheading{Remarks}

Used by the \helpref{wxDbTable::Query}{wxdbtablequery} and 
\helpref{wxDbTable::Count}{wxdbtablecount} member functions to allow outer 
joining of records from multiple tables.  

Do {\bf not} include the keyword "FROM" when setting the FROM clause.

If using the FROM clause when performing a query, be certain to include in 
the corresponding WHERE clause a comparison of a column from either the base 
table or one of the other joined tables to each other joined table to ensure 
the datasource knows on which column values the tables should be joined on.

\wxheading{Example}

\begin{verbatim}
    ...
    // Base table is the "LOCATION" table, and it is being
    // outer joined to the "PART" table via the the field "PART_NUMBER"
    // that can be related between the two tables.
    location->SetWhereClause("LOCATION.PART_NUMBER = PART.PART_NUMBER")
    location->SetFromClause("PART");
    ...
\end{verbatim}

\wxheading{See also}

\helpref{wxDbTable::From}{wxdbtablefrom}, 
\helpref{wxDbTable::SetWhereClause}{wxdbtablesetwhereclause}


\membersection{wxDbTable::SetNull}\label{wxdbtablesetnull}

\func{bool}{SetNull}{\param{int }{colNo}}

\func{bool}{SetNull}{\param{const char *}{colName}}

Both forms of this function allow a member variable representing a column 
in the table associated with this wxDbTable object to be set to NULL.

The first form allows the column to be set by the index into the column 
definitions used to create the wxDbTable instance, while the second allows 
the actual column name to be specified.

\wxheading{Parameters}

\docparam{colNo}{Index into the column definitions used when first defining 
this wxDbTable object.}
\docparam{colName}{Actual data table column name that is to be set to NULL.}

\wxheading{Remarks}

No database updates are done by this function.  It only operates on the 
member variables in memory.  Use and insert or update function to store this 
value to disk.


\membersection{wxDbTable::SetOrderByClause}\label{wxdbtablesetorderbyclause}

\func{void}{SetOrderByClause}{\param{const wxString &}{OrderBy}}

Accessor function for setting the private class member wxDbTable::orderBy 
which determines sequence/ordering of the rows returned in the result set 
of a query.

Synonym to this function is one form of \helpref{wxDbTable::OrderBy}{wxdbtableorderby}

\wxheading{Parameters}

\docparam{OrderBy}{A comma separated list of column names that indicate the 
alphabetized sorting sequence that the result set is to be returned in.  If 
a FROM clause has also been specified, each column name specified in the 
ORDER BY clause should be prefaced with the table name to which the column 
belongs using DOT notation (TABLE.COLUMN).}

\wxheading{Remarks}

Do {\bf not} include the keywords "ORDER BY" when setting the ORDER BY clause.

\wxheading{Example}

\begin{verbatim}
    ...
    parts->SetOrderByClause("PART_DESCRIP, QUANTITY");
    ...

    ...
    location->SetOrderByClause("LOCATION.POSITION, PART.PART_NUMBER);
    ...
\end{verbatim}

\wxheading{See also}

\helpref{wxDbTable::OrderBy}{wxdbtableorderby}, 
\helpref{wxDbTable::SetFromClause}{wxdbtablesetfromclause}


\membersection{wxDbTable::SetQueryTimeout}\label{wxdbtablesetquerytimeout}

\func{bool}{SetQueryTimeout}{\param{UDWORD }{nSeconds}}

Allows a time period to be set as the timeout period for queries.

\wxheading{Parameters}

\docparam{nSeconds}{The number of seconds to wait for the query to complete 
before timing out.}

\wxheading{Remarks}

Neither Oracle or Access support this function as of yet.  Other databases 
should be evaluated for support before depending on this function working 
correctly.


\membersection{wxDbTable::SetWhereClause}\label{wxdbtablesetwhereclause}

\func{void}{SetWhereClause}{\param{const wxString &}{Where}}

Accessor function for setting the private class member wxDbTable::where 
that determines which rows are returned in the result set by the datasource.

Synonym to this function is one form of \helpref{wxDbTable::Where}{wxdbtablewhere}

\wxheading{Parameters}

\docparam{Where}{SQL "where" clause.  This clause can contain any SQL language 
that is legal in standard where clauses.  If a FROM clause has also been 
specified, each column name specified in the ORDER BY clause should be 
prefaced with the table name to which the column belongs using DOT notation 
(TABLE.COLUMN).}

\wxheading{Remarks}

Do {\bf not} include the keywords "WHERE" when setting the WHERE clause.

\wxheading{Example}

\begin{verbatim}
    ...
    // Simple where clause
    parts->SetWhereClause("PART_NUMBER = '32'");
    ...
    // Any comparison operators
    parts->SetWhereClause("PART_DESCRIP LIKE 'HAMMER%'");
    ...
    // Multiple comparisons, including a function call
    parts->Where("QTY > 0 AND {fn UCASE(PART_DESCRIP)} LIKE '%DRILL%'");
    ...
    // Using parameters and multiple logical combinations
    parts->Where("((QTY > 10) OR (ON_ORDER > 0)) AND ON_HOLD = 0");
    ...
    // This query uses an outer join (requiring a FROM clause also)
    // that joins the PART and LOCATION table on he common field
    // PART_NUMBER.
    parts->Where("PART.ON_HOLD = 0 AND \
                  PART.PART_NUMBER = LOCATION.PART_NUMBER AND \
                  LOCATION.PART_NUMBER > 0");
\end{verbatim}


\membersection{wxDbTable::Update}\label{wxdbtableupdate}

\func{bool}{Update}{\void}

\func{bool}{Update}{\param{const char *}{pSqlStmt}}

This member function   

The first form of this function will update the row that the current cursor 
is currently positioned at with the values in the memory variables that 
are bound to the columns.  The actual SQL statement to perform the update 
is automatically created by the ODBC class, and then executed.

The second form of the function allows full access through SQL statements for 
updating records in the database.  Write any valid SQL UPDATE statement and 
submit it to this function for execution.  Sophisticated updates can be 
performed using the full power of the SQL dialect. The full SQL statement 
must have  the exact syntax required by the driver/datasource for performing 
the update.  This usually is in the form of:

\begin{verbatim}
    UPDATE tablename SET col1=X, col2=Y, ... where ...
\end{verbatim}

\wxheading{Parameters}

\docparam{pSqlStmt}{Pointer to SQL UPDATE statement to be executed.}

\wxheading{Remarks}

Note that using this function when it is associated with the table that the 
wxDbTable instance is associated with does not prevent updating 
columns in any other table in the database for which the connected user 
has update privileges on.  Constructing the appropriate full SQL statement, 
columns in other tables can also be updated as well.

A \helpref{wxDb::CommitTrans}{wxdbcommittrans} or 
\helpref{wxDb::RollbackTrans}{wxdbrollbacktrans} must be called after use of 
this function to commit or rollback the update.

\wxheading{Example}

\begin{verbatim}
    strcpy(sqlStmt, "update PART set QTY = 0 where PART_NUMBER = '32'");
\end{verbatim}


\membersection{wxDbTable::UpdateWhere}\label{wxdbtableupdatewhere}

\func{bool}{UpdateWhere}{\param{const char *}{pWhereClause}}

Performs updates to the base table of the wxDbTable object, updating only the 
rows which match the criteria specified in the {\it pWhereClause}.

All columns that are bound to member variables for this wxDbTable instance 
that were defined with the "updateable" parameter set to TRUE will be updated 
with the information currently held in the memory variable.  

\wxheading{Parameters}

\docparam{pWhereClause}{Pointer to a valid SQL WHERE clause.  Do not 
include the keyword 'WHERE'.}

\wxheading{Remarks}

Care should be used when updating columns that are part of indexes with 
this function so as not to violate an unique key constraints.

A \helpref{wxDb::CommitTrans}{wxdbcommittrans} or 
\helpref{wxDb::RollbackTrans}{wxdbrollbacktrans} must be called after use of 
this function to commit or rollback the update(s).


\membersection{wxDbTable::operator $++$}\label{wxdbtableplusplus}

\func{bool}{operator $++$}{\void}

Synonym for \helpref{wxDbTable::GetNext}{wxdbtablegetnext}

\wxheading{See also}

\helpref{wxDbTable::GetNext}{wxdbtablegetnext}


\membersection{wxDbTable::operator $--$}\label{wxdbtableminusminus}

\func{bool}{operator $--$}{\void}

Synonym for \helpref{wxDbTable::GetPrev}{wxdbtablegetprev}

\wxheading{See also}

\helpref{wxDbTable::GetPrev}{wxdbtablegetprev}


\section{\class{wxDbTableInf}}\label{wxdbtableinf}

Currently only used by wxDb::GetCatalog() internally and wxDbInf class,
but may be used in future releases for  user functions.  Contains information
describing the table (Name, type, etc). A pointer to a wxDbColInf array 
instance is included so a program can create a wxDbColInf array instance
(using \helpref{wxDb::GetColumns}{wxdbgetcolumns}) to maintain all information about the columns
of a table in one memory structure.