I am Sachal, working on an hiearchial IMS database, currently I am working on developing a strategy to convert IMS database to Relational Db2 database on mainframes. This is my first conversion/migration project of any kind. We have a huge database in our system, number of applications are using the same database, so if we go by pure conversion, it would take lots of money and time, so we started thinging about doing something which prevent changing the existing programs, then we came up with the idea of writing interface program between Db2 and existing program. The whole idea is not to change any program but writing out an intermediate interface program which actually simulates the IMS call over Db2. For example, all GN calls on IMS can be easily replaced by simple SQL select statements
At this point of time, I am not very sure of feasiblity, probably I am not thinking rationally, so I just wanted to know your views about the idea
I am assuming that all segments of the IMS DB can be converted into a corresponding Db2 table
you want to move your data to DB2 and probably develop new code and applications against DB2 (btw: DB2 on zOS as well or LUW?)
Same time you would like to keep existing IMS applications running and for them create an transparent gateway: the application thinks it is running against IMS but finally it is running against DB2.
What works is: with Striva you get an ODBC driver for IMS (check on that I am not 100% sure), and this could be used with Information Integrator for an transparent access on your IMS data from DB2 (probably the other way round then as you wish). Not sure whether write access is possible.
The other option: Crossaccess (bought from IBM and now part of Classic Connect and Classic Federation in Information Integration Suite): works similar by offering a transparent gateway from DB2 to IMS, and they do support updates and two-phase-commit.
Don't be confused, that it is labeled Websphere now - the whole Information Integration Suite has been renamed a year ago. IBM decided Integration belongs to Websphere rather than Data.
Well, using these tools you can have your data on one side (or on both) - but it might be necessary to replicate data over or so, since I don't know a single tool providing the native IMS -> DB2 gateway, just the other way round. It probably also depends a lot on how you access and process your IMS data today and what you are doing with it.
Well, as always on the host: licencing is not cheap. On the other hand: be happy if you manage your migration step-by-step at all at reasonable time and cost.