Use a Connection Handle When Calling SQLTransact

Performance impact: Large

You should always call SQLTransact with a valid HDBC and a null environment handle.

SQLTransact (SQL_NULL_HENV, ValidHDBC, fType)

It is possible to call SQLTransact with a non-null environment handle and a null connection handle, but that usage is not recommended as it abruptly commits or rolls back every transaction for the process, which is slow and can cause unexpected application behavior.