Re: No future for DB2

Madison Pruet wrote:
> Does Oracle snapshot replication
>
> 1) replicate all of the trigger activity performed on the original table
> 2) distinguish between updates on a row and inserts/deletes on the same row?
> (If not, then cascade deletes are not properly performed)
> 3) properly handle cascading updates

If I understand your question correctly, that is not possible with ANY replication in any database version. Traditionaly, when one replicates a table, one only wants the data of that table. What you are saying is that the entire schema potentially dependent on that table might also need to be replicated?

If so, I suggest you look at Dataguard: it's the appropriate product to achieve it and yes, it does the lot. To try and do that with replication is to pay a huge overhead to achieve something that can be done a lot more efficiently with different technology.

> This is why I generally don't consider snapshot copies as being replication.
> They generally only replicate the data, and not the engine logic associated
> with the base table.

Well, have a look at the Oracle doco. Replication has at least three flavours nowadays (four if you count Dataguard): basic, advanced and streams.
Streams is the most powerful, but being new you may pay a price in it not being entirely debugged. Of course I'm not suggesting that Oracle software is anything but perfect... ;)
The other two are just traditional replication subsets.

Have a look at Hans' reply, he details each of the two and there is no point in me repeating. Even with basic replication, you still get CRUD. But you won't get elaborate cascading dependencies. Nor trigger effect cascading. For that sort of replication, Dataguard is the answer. Received on Tue Aug 02 2005 - 01:37:32 CDT