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 (reccode == 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);
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

See Also

ODBC API Reference
ODBC Header Files