While using the Access Module for Microsoft SQL Server, the database callbacks are invoked with respect to the allocation and deallocation of the RWDBMsSqlLibEnvironmentHandle and the SQLHENV it contains. The connection callbacks are invoked with respect to the allocation, deallocation, connect and disconnect of the RWDBMsSqlLibSystemHandle and the SQLHDBC it contains. Please refer to the DB Interface Module User's Guide for more information.