Testing DL/I call sequences (DFSDDLT0) before testing your IMS program

The DL/I test program, DFSDDLT0, is an IMS application program that executes the DL/I calls you specify against any database.

An advantage of using DFSDDLT0 is that you can test the DL/I call sequence you will use prior to coding your program. Testing the DL/I call sequence before you test the program makes debugging easier, because by the time you test the program, you know that the DL/I calls are correct. When you test the program, and it does not execute correctly, you know that the DL/I calls are not part of the problem if you have already tested them using DFSDDLT0.

For each DL/I call that you want to test, you give DFSDDLT0 the call and any SSAs that you are using with the call. DFSDDLT0 then executes and gives you the results of the call. After each call, DFSDDLT0 shows you the contents of the DB PCB mask and the I/O area. This means that for each call, DFSDDLT0 checks the access path you have defined for the segment, and the effect of the call. DFSDDLT0 is helpful in debugging because it can display IMS application control blocks.

To indicate to DFSDDLT0 the call you want executed, you use four types of control statements:

• Status statements establish print options for DFSDDLT0's output and select the DB PCB to use for the calls you specify.
• Comment statements let you choose whether you want to supply comments.
• Call statements indicate to DFSDDLT0 the call you want to execute, any SSAs you want used with the call, and how many times you want the call executed.
• Compare statements tell DFSDDLT0 that you want it to compare its results after executing the call with the results you supply.

In addition to testing call sequences to see if they work, you can also use DFSDDLT0 to check the performance of call sequences.