Re: Road Map to move a home grown application from RPG to DB2 SQL or to any other data base platform

SQL and RLA compliment one another rather than compete.

creating tables with SQL DDL and using RLA, as some experts recommend, is a bad practice, you are falling bacl behind DDS defined join files. tumbling around in the database to grab together data, a join operation would deliver easily. Another weakness of RLA is: the tight coupling from database implementation and application.

In regards to ORMs, they are an example of OO taken to an extreme. They add
a ton of overhead. The facilitate the movement of business rules into
language environments which are not well suited for that kind of
processing, they create a sense that a DBMS is merely a "persistence"
layer. I think ORMs cause more harm than they do good.

lt looks like you are talking about something, you've never used, nor having had a deeper look to it. ORMs have overhead (you never will get something for nothing, everything has its price!), but it's often over compensated by its caching possibilities and its configurable loading strategies (loading on demand versus pre fetching, as you need).

The real problem with moving business logic (you might name it business rules, if this is more convinient for you) to the database is loss of maintainebility and flexibility. Changes to this logic could have many side effects and error situations could be very hard to analyze. A relational database should do, what it is designed for: store data, ensure relational constraints and provide transaction handling (BTW: commitment controll is an absolutely must have for SQL access and using naming *SYS accessing database tables with *LIBL stands in contrdiction to referential integrity!!!)

D*B