VSAM Data Migration

diwa_thilak · Posted: Sat Apr 05, 2008 2:34 am Post subject: VSAM Data Migration

Hi Friends,

My new assignment is to migrate the data from VSAM files into Oracle tables for testing an open system application.

What are the criteria's i need to consider for this migration ?

What are the prerequiste i need to define as a to do for the open systems ?

If anybody got any checklist kinda of thing, you can share it with me.

I need to calculate the table size / volume of data , how can i calculate these using my VSAM files.

dick scherrer · Posted: Sat Apr 05, 2008 2:44 am Post subject:

Hello,

Possibly an early thought should be if the vsam files are going to be loaded 1-for-1 into oracle tables or if there will be some re-design. If there are any repeating groups or redefines (very common in vsam), there will be some redesign.

My experience has been that if the data is created in oracle-loadable format on the mainframe as a set of delimited text files the data movement goes much smoother.

Once the oracle table structure definitions are in place, determine how many download records there will be of each format and multiply by record length. This is a starting number for that table's data size. You will also need to consider how much overhead there will be for index entries. To guestimate the number/size of index entries for the oracle tables, you might use the existing vsam key definitions for a starting point.

I suggest that you plan on doing this iteratively. As you learn, refine the end size needed for the final oracle database.

diwa_thilak · Posted: Tue Apr 08, 2008 7:17 pm Post subject:

Thanks for your reply dick.

Can you tell me how to go about going to handle the packed decimal formats.

I need to consider them as well rt ? (while getting into delimited text files.)

Any other views/suggestions from your part.

A better way to approach this project. May be your experience can guide me better.

Thanks for your help in advance.

dick scherrer · Posted: Tue Apr 08, 2008 7:28 pm Post subject:

Hello,

What has worked well at several places i've supported is to have a bit of code (or possibly the sort product) "copy" the vsam data to delimited qsam files (in the format that is needed to load into oracle). Doing a proper job "up front" may take a bit more time, but saves an incredible amount of time fighting with unusable data later.

This includes getting "everything" into text that is delimiter-separated. Simply moving numeric data to a properly edited field on the mainframe will do what you want. Packed, binary, and zoned numerics can be moved to something like zzzzz.99- (pick whatever size is right for the field) and will load easily).