SQLGetFunctions
Version Introduced: ODBC 1.0
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(
Arguments
ConnectionHandle [Input]
FunctionId [Input]
For a list of #define values that identify ODBC functions, see the tables in “Comments.”
SupportedPtr [Output]
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 3.0 or earlier function
is supported. The SQL_FUNC_EXISTS macro is called to determine function support
(see “Comments”). An ODBC 3.0 application can call SQLGetFunctions with SQL_API_ODBC3_ALL_FUNCTIONS against either an ODBC 3.0 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.
Standards Compliance: ISO 92
SQLHDBC ConnectionHandle,
SQLUSMALLINT FunctionId,
SQLUSMALLINT * SupportedPtr);
Connection handle.
A #define value that identifies the ODBC function of interest;
SQL_API_ODBC3_ALL_FUNCTIONS or SQL_API_ALL_FUNCTIONS. SQL_API_ODBC3_ALL_FUNCTIONS is used by an ODBC
3.0 application to determine support of ODBC 3.0 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.
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.
| 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. |
| 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.
|
| 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.
|
SQLGetFunctions always returns that SQLGetFunctions, SQLDataSources, and SQLDrivers are supported. It does this because these functions are implemented in the Driver Manager. For information about how applications use SQLGetFunctions, see “Interface Conformance Levels” in Chapter 4, “ODBC Fundamentals.”
The following is a list of valid values for FunctionId for functions that conform to the ISO 92 standards–compliance level:
| 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
|
|
| SQL_API_SQLCOLUMNS
| SQL_API_SQLSTATISTICS
|
| SQL_API_SQLSPECIALCOLUMNS
| SQL_API_SQLTABLES
|
| 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 SQL_FUNC_EXISTS(SupportedPtr, FunctionID) macro is used to determine support of ODBC 3.0 or earlier functions after SQLGetFunctions has been called with an 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 3.0 Driver Manager will return SQL_TRUE for SQLAllocHandle and SQLFreeHandle, because SQLAllocHandle is mapped to SQLAllocEnv, SQLAllocConnect, or SQLAllocStmt, and 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 two 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;
SQLGetFunctions(hdbc, SQL_API_SQLTABLES, &TablesExists);
SQLGetFunctions(hdbc, SQL_API_SQLCOLUMNS, &ColumnsExists);
SQLGetFunctions(hdbc, SQL_API_SQLSTATISTICS, &StatisticsExists);
if (TablesExists && ColumnsExists && StatisticsExists) {
/* Continue with application */
}
SQLDisconnect(hdbc);
The second example calls SQLGetFunctions a single time and passes it an array in which SQLGetFunctions returns information about all ODBC functions.
#define FUNCTIONS 100
SQLUSMALLINT fExists[FUNCTIONS];
SQLGetFunctions(hdbc, SQL_API_ALL_FUNCTIONS, fExists);
if (fExists[SQL_API_SQLTABLES] &&
fExists[SQL_API_SQLCOLUMNS] &&
fExists[SQL_API_SQLSTATISTICS]) {
/* Continue with application */
}
SQLDisconnect(hdbc);
Related Functions
| For information about
| See
|
Returning the setting of a connection attribute | SQLGetConnectAttr
|
| Returning information about a driver or data source
| SQLGetInfo
|
| Returning the setting of a statement attribute
| SQLGetStmtAttr
|