FM/IMS Database Compare

This Idea is for a FM/IMS function to do a formatted/synchronized database compare. The goal is to compare a database before and after it is changed, to report on what changed.

This is probably a multi-step process:

1. Generate and run a batch job to capture the "before" view of the database.

2. User does something to the database, external to FM/IMS.

3. Run the database compare, using the file from step 1 as the input along with the current view of the database. It is OK if what this step actually does is...

   1. Capture the "after" view of the database

   2. Compare the before and after versions.

The compare should be a synchronized compare, and if a template library is supplied, then there should be the option for a formatted compare, similar to the FM/Base product.

That is, it should:

1. Compare segments, matching on the segment name and concatenated key.

2. Report segments that are inserted (new key) or deleted (key no longer exists)

3. For segments that are changed, report what changed at a field level using the template.

The format of the Audit Trail report would work.

Since the compare function needs to capture the state of the database, one way to look at this is as a combination of the Extract function, and a Compare function that works using FM/IMS extract format files. It would be OK if that's exactly how it works: the capture is an Extract function step, and there's a new Compare function that compares extract files. One advantage to this concept is that you'd be able to use all the capabilities of the Extract function to filter which records and segments are extracted, and therefore compared.

Note: I previously proposed this idea to IBM on 1/26/2005 as Marketing Request MR0228053838. The last status I heard was "Acknowledged". I haven't heard anything about it in 17 years so I'm submitting it again.