Query Validation Exit

Query Validation Exit

CA Dataquery supports a user Query Validation Exit which allows you to enforce site standards. You can code the exit to the following:

• Analyze the contents of a query
• Modify the query
• Continue processing as usual
• Reject the query

Operation

A query can be rejected by your Query Validation Exit with a standard error message or a special error code to be used in conjunction with panels 990 through 999 as described in the information about register 15 below. (See DQOPTLST Parameters for more information about the VALEXIT= parameter of the System Option Table.)

Procedure

CA Dataquery provides ten panels that can be used to document errors that may result from tailoring your system. If you set return code 990-999, CA Dataquery will give error panels 990-999. You can create error messages.

Code this exit in the Assembler language. Make it reentrant or reusable. It must be linked to the CA Dataquery load library and have a PPT entry if under CICS.

Monitor calls and I/O requests cannot be issued by the Query Validation Exit.

When writing the exit, note the following register conventions:

Register 1

Points to a parameter list consisting of the following entries (in order from the beginning of the list):

• Address of an area that contains the query to be edited. The length is determined from the option table. The length is the value of the QPAGES= parameter times 24.
• Address of an area, 32 characters long, that contains the user's signon ID, left justified and blank filled on the right.
• Address of a 256-byte area (doubleword aligned) to be used as needed by the exit. The area is not initialized on entry.

Register 13

Contains the address of a register SAVE area which you must use to save and restore CA Dataquery's registers according to standard linkage conventions.

Register 14

Contains the return address within CA Dataquery.

Register 15

Contains the address of the entry point of the exit.

Prior to returning control to CA Dataquery, the exit must place one of the following return codes in register 15.

• 0 signifies a normal return.

  The exit passes back to CA Dataquery the query pointed at by the first entry of the parameter list. (The query may have been modified as specified by the exit.)

• 990—999 or any nonzero code signifies an error return.

  CA Dataquery issues user written error panels based on the decimal value in register 15 (990—999). The system suspends further edit processing for the query.

  You can use special error codes 990 through 999 in conjunction with panels 990 through 999. Panels 990—999 can be customized with error messages of your own choosing.

• Any nonzero return code other than 990—999 suspends processing with error message DQ048E, with return code displayed.

See DBID Exit for an explanation of return codes and their meanings.

Implementation

To implement the Query Validation Exit:

1. Code the VALEXIT= parameter in the DQOPTLST macro and reassemble the CA Dataquery System Option Table. (See :spotref refid=valex for more information about the VALEXIT= parameter of the System Option Table.)
2. If running under CICS/VS:
   1. Assemble and link edit the user exit into the regular CICS program library under the name specified in the VALEXIT= parameter.
   2. Add an entry for the exit to the CICS PPT.

For samples, see the CA Datacom website.