Q and A

Asked and Answered

IMS vs. DDF

My company uses IMS a lot. About 3 to 5 years ago we started developing IBM' s VisualAge Smalltalk applications to run on the clients. [These applications] would initiate IMS transactions to access DB2. We no longer use Smalltalk. Would you say that DDF is a good alternative to IMS? All our new developers seem to be using JavaBeans, and some have started experimenting with JDBC.

Sincerely,

JR Shukla
Fort Worth, Tex.

Robert Catterall responds:

Yes, DDF is a viable alternative to IMS for transactional access to DB2. Just keep in mind that IMS-DB2 transactions are fast largely because they employ static, server-side SQL statements. DDF-based applications can do the same via stored procedures, and a stored procedure can be invoked via JDBC. Of course, if the transactions have, on average, only a few SQL statements (say, five or fewer per transaction, not counting FETCH statements), client-side SQL can deliver good performance, particularly if the SQL statements are pre-bound into packages (as can be done when you use SQLJ in Java programs). I know of an insurance company that drives about 60 relatively simple (average of four SQL statements each) transactions per second through DB2 Connect and DDF during a peak hour, and they use embedded, client-side SQL.

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