SQLGetFunctions Function
Conformance
Version Introduced: ODBC 1.0 Standards Compliance: ISO 92
Summary
SQLGetFunctions returns information about whether a driver supports a specific ODBC function. This function is implemented in the Driver Manager; it can also be implemented in drivers. If a driver implements SQLGetFunctions, the Driver Manager calls the function in the driver. Otherwise, it executes the function itself.
Syntax
SQLRETURN SQLGetFunctions(
SQLHDBC ConnectionHandle,
SQLUSMALLINT FunctionId,
SQLUSMALLINT * SupportedPtr);
Arguments
ConnectionHandle
[Input] Connection handle.
FunctionId
[Input] A #define value that identifies the ODBC function of interest; SQL_API_ODBC3_ALL_FUNCTIONS orSQL_API_ALL_FUNCTIONS. SQL_API_ODBC3_ALL_FUNCTIONS is used by an ODBC 3*.x* application to determine support of ODBC 3*.x* and earlier functions. SQL_API_ALL_FUNCTIONS is used by an ODBC 2*.x* application to determine support of ODBC 2*.x* and earlier functions.
For a list of #define values that identify ODBC functions, see the tables in "Comments."
SupportedPtr
[Output] If FunctionId identifies a single ODBC function, SupportedPtr points to a single SQLUSMALLINT value that is SQL_TRUE if the specified function is supported by the driver, and SQL_FALSE if it is not supported.
If FunctionId is SQL_API_ODBC3_ALL_FUNCTIONS, SupportedPtr points to a SQLSMALLINT array with a number of elements equal to SQL_API_ODBC3_ALL_FUNCTIONS_SIZE. This array is treated by the Driver Manager as a 4,000-bit bitmap that can be used to determine whether an ODBC 3*.x* or earlier function is supported. The SQL_FUNC_EXISTS macro is called to determine function support. (See "Comments.") An ODBC 3*.x* application can call SQLGetFunctions with SQL_API_ODBC3_ALL_FUNCTIONS against either an ODBC 3*.x* or ODBC 2*.x* driver.
If FunctionId is SQL_API_ALL_FUNCTIONS, SupportedPtr points to an SQLUSMALLINT array of 100 elements. The array is indexed by #define values used by FunctionId to identify each ODBC function; some elements of the array are unused and reserved for future use. An element is SQL_TRUE if it identifies an ODBC 2*.x* or earlier function supported by the driver. It is SQL_FALSE if it identifies an ODBC function not supported by the driver or does not identify an ODBC function.
The arrays returned in *SupportedPtr use zero-based indexing.
Returns
SQL_SUCCESS, SQL_SUCCESS_WITH_INFO, SQL_ERROR, or SQL_INVALID_HANDLE.
Diagnostics
When SQLGetFunctions returns SQL_ERROR or SQL_SUCCESS_WITH_INFO, an associated SQLSTATE value can be obtained by calling SQLGetDiagRec with a HandleType of SQL_HANDLE_DBC and a Handle of ConnectionHandle. The following table lists the SQLSTATE values commonly returned by SQLGetFunctions and explains each one in the context of this function; the notation "(DM)" precedes the descriptions of SQLSTATEs returned by the Driver Manager. The return code associated with each SQLSTATE value is SQL_ERROR, unless noted otherwise.
| SQLSTATE | Error | Description |
|---|---|---|
| 01000 | General warning | Driver-specific informational message. (Function returns SQL_SUCCESS_WITH_INFO.) |
| 08S01 | Communication link failure | The communication link between the driver and the data source to which the driver was connected failed before the function completed processing. |
| HY000 | General error | An error occurred for which there was no specific SQLSTATE and for which no implementation-specific SQLSTATE was defined. The error message returned by SQLGetDiagRec in the *MessageText buffer describes the error and its cause. |
| HY001 | Memory allocation error | The driver was unable to allocate memory required to support execution or completion of the function. |
| HY010 | Function sequence error | (DM) SQLGetFunctions was called before SQLConnect, SQLBrowseConnect, or SQLDriverConnect. (DM) SQLBrowseConnect was called for the ConnectionHandle and returned SQL_NEED_DATA. This function was called before SQLBrowseConnect returned SQL_SUCCESS_WITH_INFO or SQL_SUCCESS. (DM) SQLExecute, SQLExecDirect, or SQLMoreResults was called for the ConnectionHandle and returned SQL_PARAM_DATA_AVAILABLE. This function was called before data was retrieved for all streamed parameters. |
| HY013 | Memory management error | The function call could not be processed because the underlying memory objects could not be accessed, possibly because of low memory conditions. |
| HY095 | Function type out of range | (DM) An invalid FunctionId value was specified. |
| HY117 | Connection is suspended due to unknown transaction state. Only disconnect and read-only functions are allowed. | (DM) For more information about suspended state, see SQLEndTran Function. |
| HYT01 | Connection timeout expired | The connection timeout period expired before the data source responded to the request. The connection timeout period is set through SQLSetConnectAttr, SQL_ATTR_CONNECTION_TIMEOUT. |
Comments
SQLGetFunctions always returns that SQLGetFunctions, SQLDataSources, and SQLDrivers are supported. It does this because these functions are implemented in the Driver Manager. The Driver Manager will map an ANSI function to the corresponding Unicode function if the Unicode function exists and will map a Unicode function to the corresponding ANSI function if the ANSI function exists. For information about how applications use SQLGetFunctions, see Interface Conformance Levels.
The following is a list of valid values for FunctionId for functions that conform to the ISO 92 standards-compliance level:
| FunctionId Value | FunctionId Value |
|---|---|
| SQL_API_SQLALLOCHANDLE | SQL_API_SQLGETDESCFIELD |
| SQL_API_SQLBINDCOL | SQL_API_SQLGETDESCREC |
| SQL_API_SQLCANCEL | SQL_API_SQLGETDIAGFIELD |
| SQL_API_SQLCLOSECURSOR | SQL_API_SQLGETDIAGREC |
| SQL_API_SQLCOLATTRIBUTE | SQL_API_SQLGETENVATTR |
| SQL_API_SQLCONNECT | SQL_API_SQLGETFUNCTIONS |
| SQL_API_SQLCOPYDESC | SQL_API_SQLGETINFO |
| SQL_API_SQLDATASOURCES | SQL_API_SQLGETSTMTATTR |
| SQL_API_SQLDESCRIBECOL | SQL_API_SQLGETTYPEINFO |
| SQL_API_SQLDISCONNECT | SQL_API_SQLNUMRESULTCOLS |
| SQL_API_SQLDRIVERS | SQL_API_SQLPARAMDATA |
| SQL_API_SQLENDTRAN | SQL_API_SQLPREPARE |
| SQL_API_SQLEXECDIRECT | SQL_API_SQLPUTDATA |
| SQL_API_SQLEXECUTE | SQL_API_SQLROWCOUNT |
| SQL_API_SQLFETCH | SQL_API_SQLSETCONNECTATTR |
| SQL_API_SQLFETCHSCROLL | SQL_API_SQLSETCURSORNAME |
| SQL_API_SQLFREEHANDLE | SQL_API_SQLSETDESCFIELD |
| SQL_API_SQLFREESTMT | SQL_API_SQLSETDESCREC |
| SQL_API_SQLGETCONNECTATTR | SQL_API_SQLSETENVATTR |
| SQL_API_SQLGETCURSORNAME | SQL_API_SQLSETSTMTATTR |
| SQL_API_SQLGETDATA |
The following is a list of valid values for FunctionId for functions conforming to the Open Group standards-compliance level:
| FunctionId Value | FunctionId Value |
|---|---|
| SQL_API_SQLCOLUMNS | SQL_API_SQLSTATISTICS |
| SQL_API_SQLSPECIALCOLUMNS | SQL_API_SQLTABLES |
The following is a list of valid values for FunctionId for functions conforming to the ODBC standards-compliance level.
| FunctionId Value | FunctionId Value |
|---|---|
| SQL_API_SQLBINDPARAMETER | SQL_API_SQLNATIVESQL |
| SQL_API_SQLBROWSECONNECT | SQL_API_SQLNUMPARAMS |
| SQL_API_SQLBULKOPERATIONS[1] | SQL_API_SQLPRIMARYKEYS |
| SQL_API_SQLCOLUMNPRIVILEGES | SQL_API_SQLPROCEDURECOLUMNS |
| SQL_API_SQLDESCRIBEPARAM | SQL_API_SQLPROCEDURES |
| SQL_API_SQLDRIVERCONNECT | SQL_API_SQLSETPOS |
| SQL_API_SQLFOREIGNKEYS | SQL_API_SQLTABLEPRIVILEGES |
| SQL_API_SQLMORERESULTS |
[1] When working with an ODBC 2*.x* driver, SQLBulkOperations will be returned as supported only if both of the following are true: the ODBC 2*.x* driver supports SQLSetPos, and the information type SQL_POS_OPERATIONS returns the SQL_POS_ADD bit as set.
The following is a list of valid values for FunctionId for functions introduced in ODBC 3.8 or later:
| FunctionId Value |
|---|
| SQL_API_SQLCANCELHANDLE [2] |
[2] SQLCancelHandle will be returned as supported only if the driver supports both SQLCancel and SQLCancelHandle. If SQLCancel is supported but SQLCancelHandle is not, the application can still call SQLCancelHandle on a statement handle, because it will be mapped to SQLCancel.
SQL_FUNC_EXISTS Macro
The SQL_FUNC_EXISTS(SupportedPtr, FunctionID) macro is used to determine support of ODBC 3*.x* or earlier functions after SQLGetFunctions has been called with a FunctionId argument of SQL_API_ODBC3_ALL_FUNCTIONS. The application calls SQL_FUNC_EXISTS with the SupportedPtr argument set to the SupportedPtr passed in SQLGetFunctions, and with the FunctionID argument set to the #define for the function. SQL_FUNC_EXISTS returns SQL_TRUE if the function is supported, and SQL_FALSE otherwise.
Note
When working with an ODBC 2*.x* driver, the ODBC 3*.x* Driver Manager will return SQL_TRUE for SQLAllocHandle and SQLFreeHandle because SQLAllocHandle is mapped to SQLAllocEnv, SQLAllocConnect, or SQLAllocStmt, and because SQLFreeHandle is mapped to SQLFreeEnv, SQLFreeConnect, or SQLFreeStmt. SQLAllocHandle or SQLFreeHandle with a HandleType argument of SQL_HANDLE_DESC is not supported, however, even though SQL_TRUE is returned for the functions, because there is no ODBC 2*.x* function to map to in this case.
Code Example
The following three examples show how an application uses SQLGetFunctions to determine if a driver supports SQLTables, SQLColumns, and SQLStatistics. If the driver does not support these functions, the application disconnects from the driver. The first example calls SQLGetFunctions once for each function.
SQLUSMALLINT TablesExists, ColumnsExists, StatisticsExists;
RETCODE retcodeTables, retcodeColumns, retcodeStatistics
retcodeTables = SQLGetFunctions(hdbc, SQL_API_SQLTABLES, &TablesExists);
retcodeColumns = SQLGetFunctions(hdbc, SQL_API_SQLCOLUMNS, &ColumnsExists);
retcodeStatistics = SQLGetFunctions(hdbc, SQL_API_SQLSTATISTICS, &StatisticsExists);
// SQLGetFunctions is completed successfully and SQLTables, SQLColumns, and SQLStatistics are supported by the driver.
if (retcodeTables == SQL_SUCCESS && TablesExists == SQL_TRUE &&
retcodeColumns == SQL_SUCCESS && ColumnsExists == SQL_TRUE &&
retcodeStatistics == SQL_SUCCESS && StatisticsExists == SQL_TRUE)
{
// Continue with application
}
SQLDisconnect(hdbc);
In the second example, an ODBC 3.x application calls SQLGetFunctions and passes it an array in which SQLGetFunctions returns information about all ODBC 3.x and earlier functions.
RETCODE retcodeTables, retcodeColumns, retcodeStatistics
SQLUSMALLINT fExists[SQL_API_ODBC3_ALL_FUNCTIONS_SIZE];
retcode = SQLGetFunctions(hdbc, SQL_API_ODBC3_ALL_FUNCTIONS, fExists);
// SQLGetFunctions is completed successfully and SQLTables, SQLColumns, and SQLStatistics are supported by the driver.
if (retcode == SQL_SUCCESS &&
SQL_FUNC_EXISTS(fExists, SQL_API_SQLTABLES) == SQL_TRUE &&
SQL_FUNC_EXISTS(fExists, SQL_API_SQLCOLUMNS) == SQL_TRUE &&
SQL_FUNC_EXISTS(fExists, SQL_API_SQLSTATISTICS) == SQL_TRUE)
{
// Continue with application
}
SQLDisconnect(hdbc);
The third example is an ODBC 2.x application calls SQLGetFunctions and passes it an array of 100 elements in which SQLGetFunctions returns information about all ODBC 2.x and earlier functions.
#define FUNCTIONS 100
RETCODE retcodeTables, retcodeColumns, retcodeStatistics
SQLUSMALLINT fExists[FUNCTIONS];
retcode = SQLGetFunctions(hdbc, SQL_API_ALL_FUNCTIONS, fExists);
/* SQLGetFunctions is completed successfully and SQLTables, SQLColumns, and SQLStatistics are supported by the driver. */
if (retcode == SQL_SUCCESS &&
fExists[SQL_API_SQLTABLES] == SQL_TRUE &&
fExists[SQL_API_SQLCOLUMNS] == SQL_TRUE &&
fExists[SQL_API_SQLSTATISTICS] == SQL_TRUE)
{
/* Continue with application */
}
SQLDisconnect(hdbc);
Related Functions
| For information about | See |
|---|---|
| Returning the setting of a connection attribute | SQLGetConnectAttr Function |
| Returning information about a driver or data source | SQLGetInfo Function |
| Returning the setting of a statement attribute | SQLGetStmtAttr Function |