Re: Getting Role and Permissions from DB

Hi Thomas:

Thank you very much for your detail explanation. I still have some questions.

Thomas Kyte (tkyte_at_us.oracle.com) wrote:

: A simple view, as I describe above "select c1, c2, c3 from T" will not affect
: performance (except perhaps during the initial parse phase of the query but that
: will be neglible).

: the 'problem' people sometimes see with views is that they create join or
: aggregate views. Then, they create join or aggregate views on top of these and
: so on... Then, people take 2 or 3 of these views at runtime and query them
: together. the optimizer has a hard time merging these views together and
: pushing predicates down. A 'hand written' query with no views in this case will
: probably be more performant.

: It can be hard to tune systems with lots of complex underlying views and queries
: against these views. I'm not suggesting that however, far from it.

If I have a query with a lot of joints and it may be called by a group of people e.g. developers for billing related process, will it be benefit to put it into a view?

: In your case, your main problem is the grants. Using simple:

: SQL> create or replace view my_view as select * from t;

: with no joins, no aggregates, etc should not have any impact on the query plans
: (i've never seen any with simple views).

Yes, this one very clear. I got it.

Once again, tahnk you veyr much for your time.

Best regards, Received on Sun Jan 03 1999 - 18:16:14 CST