When using the DB Access Module for Sybase, the database callbacks are invoked with respect to the allocation and deallocation of Sybase Client-Library Context Handle CS_CONTEXT. The connection callbacks are invoked with respect to the allocation, deallocation, connect and disconnect of the Sybase Client-Library Connection Handle CS_CONNECTION. Please refer to the DB Interface Module User's Guide for more information.

When using the XA Access Module for Sybase, the module does not allocate and deallocate CS_CONTEXT and CS_CONNECTION handles; it just fetches them. Hence, the database callbacks are invoked before and after fetching the CS_CONTEXT. Callbacks preConnAllocate, postConnAllocate and preConnect are called before fetching the CS_CONNECTION. Callback postConnect is called after fetching the CS_CONNECTION.