Re: Gotchas while migrating from DB2 to Oracle.

Hemant Shah <shah_at_typhoon.xnet.com> wrote in message news:<br590p$12d$1_at_flood.xnet.com>...

> was pretty lively. It seems Oracle will not block readers, and that
> difference (from DB2) has significant impact on our application.

It should not cause major problems. If the functionality of Oracle is a problem (why?), then use SELECT ... FOR UPDATE as the syntax for your "block-on-read" implementation. It will achieve the same result.

ATTENTION: ONLY use the syntax "FOR UPDATE" when you indeed want to lock a SINGLE row on a read. If you do not need to lock on read, then DON'T!

> For people who has used DB2 and Oracle can you please tell me other
> differences you have found so that I can be prepared, or point me to a
> document/web page.

Daniel gave you a very good list. BE aware that PL/SQL packages when used in triggers, provide a much more powerful facility than the stored SQL ANSI standard used in DB2. In addition you can use native Java with Oracle FROM the database as stored code. That is not directly possible with DB2, so therein may lie a useful optimisation.

> We are porting our application from DB2 UDB (7.2) to Oracle 9i (9.2.0.4.0).

If you want to keep DB2 compatibility it will be a lot harder. If not, I urge you to use the features of 9i over and above what DB2 7 provides. Tom Kyte's books provide excellent reference material for this sort of thing. If you don't have to keep compatibility, then DO USE the extras you get in 9i: it's well worth it!

Cheers
Nuno Souto
wizofoz2k_at_yahoo.com.au.nospam Received on Wed Dec 10 2003 - 00:57:42 CST