ASA Programming Guide
ODBC Programming
ODBC handles
The handle types required for ODBC programs are as follows:
| Item | Handle type |
|---|---|
| Environment |
SQLHENV
|
| Connection |
SQLHDBC
|
| Statement |
SQLHSTMT
|
| Descriptor |
SQLHDESC
|
To use an ODBC handle
Call the SQLAllocHandle function.
SQLAllocHandle takes the following parameters:
an identifier for the type of item being allocated
the handle of the parent item
a pointer to the location of the handle to be allocated
For a full description, see
SQLAllocHandle in the Microsoft ODBC Programmer's Reference.
Use the handle in subsequent function calls.
Free the object using SQLFreeHandle.
SQLFreeHandle takes the following parameters:
an identifier for the type of item being freed
the handle of the item being freed
For a full description, see
SQLFreeHandle in the Microsoft ODBC Programmer's Reference.
The following code fragment allocates and frees an environment handle:
SQLHENV env;
SQLRETURN retcode;
retcode = SQLAllocHandle(
SQL_HANDLE_ENV,
SQL_NULL_HANDLE,
&env );
if( retcode == SQL_SUCCESS
|| retcode == SQL_SUCCESS_WITH_INFO ) {
// success: application code here
}
SQLFreeHandle( SQL_HANDLE_ENV, env );For more information on return codes and error handling, see Handling errors.