Data Capture call functions

Data Capture exit routines are called when segment data is updated by an application program insert, replace, or delete call. If subset pointer updates are to be captured (SSPCMD), get calls will also be captured.

This topic contains Product-sensitive Programming Interface information.

Optionally, Data Capture exit routines are called when DL/I deletes a dependent segment because the application program deleted its parent segment, a process that is known as cascade delete. Data Capture exit routines are passed two functions to identify the following:
  1. The action performed by the application program
  2. The action performed by IMS
The two functions that are passed to the Data Capture exit routines are:
  • Call function. The DL/I call, ISRT, REPL, Gx (get-type), or DLET, that is issued by the application program for the segment.
  • Physical function. The physical action, ISRT, REPL, or DLET, performed by IMS as a result of the call. Physical function SSPU is set for segments that are not updated but have subset pointers updates. The physical function is used to determine the type of SQL request to issue when propagating data.
The call and physical functions passed to the exit routine are always the same for replace calls. However, the functions passed might differ for delete or insert calls:
  • For delete calls resulting in cascade deletes, the call function passed is CASC (to indicate the cascade delete) and the physical function passed is DLET.
  • For insert calls resulting in the insert of a logical child and the replace of a logical parent (because the logical parent already exists), the call function that is passed is ISRT and the physical function that is passed is REPL. IMS physically replaces the logical parent with data inserted by the application program even if the parent data does not change. Both call and physical functions are then used, based on the data propagation requirements, to determine the SQL request to issue in the Data Capture exit routine.

If the job name of a CCTL or ODBM address space is specified on the SUPPDCAPNAME= parameter in the DFSDFxxx member of the IMS PROCLIB data set, the Data Capture exit routine is not called for updates that are invoked by the specified job.