Re: Using views inside a View

From: Frank van Bortel <fvanbortel_at_netscape.net>
Date: Tue, 22 Feb 2005 20:23:36 +0100
Message-ID: <cvg0no$sir$1@news2.zwoll1.ov.home.nl>

GreyBeard wrote:
> On Tue, 22 Feb 2005 10:19:52 +0100, Frank van Bortel wrote:
>
>

>>>Back to this one - would it be fair to provide the following ROT to the
>>>OP's question:
>>>
>>>"The technical issues that caused performance concerns related to nested
>>>views in [very old] versions of Oracle are, for the largest part, no
>>>longer relevant.  
>>>
>>>However, inappropriate use of views can have side effects such as
>>>unacceptable performance and resource issues.  These side effects, such as
>>>unnecessary aggregation within views, could become significant in ad-hoc
>>>environments.
>>>
>>>Suitable documentation for views as well as proper analysis, including
>>>explain plans, should be considered for all 'permanent' SQL statements."
>>>
>>>FGB
>>
>>I like that - it may just be a little long for a ROT.
>>The part that sticks will probably be just the first
>>sentence, which is OK by me for a ROT.

>
>
> You're right - I tend to be wordy. Let's try this on for size:
>
> "Careless (or novice) use of nested views can have issues because of side
> effects of unseen operations such as aggregations.
>
> Careful use of relevant and documented views should not (normally) have
> performance impacts.
>
> Make sure you test."
>
> FGB
lol

That's at least one rule: test.
And perhaps another: document (what was tested).

How about agreeing we agree? This is getting a bit OT

-- 
Regards,
Frank van Bortel

Received on Tue Feb 22 2005 - 13:23:36 CST