Re: Display only part of resultset (ORA 8.1.7)

On Wed, 24 Dec 2003, fbortel_at_nescape.net wrote:
> Galen Boyer wrote:
>
>> On Tue, 23 Dec 2003, fbortel_at_nescape.net wrote:
>>
>>>Don't use the view! Use the underlying query instead;
>>>it'll give Oracle the opportunity to use a better plan.
>>>
>>>Rule # 7: do not use views in joins (modified)
>> Care to explain?
>
> A view itself has an underlying query. I have seen too much
> code, based on joins of views leading to, eerrr, sub-optimal
> performance.
>
> Rule #7 of some Basic Performance Tips document stated not to
> code joins over views, but use the underlying statement, or
> create a new view.
> The modification is mine: there's no join here.

I just think it is silly to have this type of rule. I've coded loads of views that have joins to other views within them and have not seen problems, but, then again, I know they could arise so I sprinkle that knowledge in the original coding effort.

Views and joins to them are very good tools. Don't make some RULE that has no merit just because, sometimes you have seen views on views give bad performance.

-- 
Galen Boyer