Re: is there any point to use materialized view without db link?

niy38_at_hotmail.com wrote:

> in that secenario, a view seem more meaningful: without use extra space.
>

Materialized views play two similar roles in two very different contexts.

In the data warehouse context (without any DB links), they play a role in performance improvement, as implied by DA Morgan in his reply ("query rewrite"). Your question (or statement, it seems) is that "a view seem more meaningful: without use extra space", but with a view, you lose the tremendous performance boost due to "pre-querying" your data. Hmm, space versus time trade-off ... ;-)

In the Advanced Replication context, MV's were previously known as "snapshots" and did indeed rely on DB links -- essentially, the incremental changes to a table (or view) in the source database were replicated to another database (the replication target) via snapshot logs (MV logs) and refresh of the snapshot (MV) at the target. This usage is still supported, but is deprecated in favor of Oracle Streams replication.

-Mark Bole Received on Thu Oct 13 2005 - 21:24:44 CDT