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Re: Using views inside a View

From: Frank van Bortel <>
Date: Mon, 21 Feb 2005 11:35:20 +0100
Message-ID: <cvcddc$ur4$>

GreyBeard wrote:
> On Thu, 17 Feb 2005 04:08:37 -0800, muneerhassan wrote:

>>Is there any performance problem when using a view inside a view. I
>>dont find any performance issue as such. Our client is insisting that
>>their standard wont allow to use views inside views. But i feel by
>>using views inside views, developers are finding it more easy to write
>>bug free queries which are more logicaly organized. Is there any
>>advantage or draw backs in following this practice. Pls shed light on
>>this .

> You client is absolutely correct - I found in Oracle version 5 and early
> Oracle version 6 there were significant performance problems that arose
> from nested views.
> However, many of these were resolved in Oracle 7. If your client is using
> any currently supported version of Oracle, there should be no hesitation
> in nesting views - provided suitable supporting documentation describing
> their purpose and implementation is provided.
> Seems like your client had standards created some time ago, and no one was
> smart enough to keep on top of them.
> Since only money talks, you probably want to get a copy of Thomas Kyte's
> "Effective Oracle by Design" and implement his timing routines - then
> prove to your client that there is no runtime impact to nested views. A
> ROI case can then be generated to prove that developer efficiency is
> actually reducing client's costs.
> (By the way, tell them they can use the Cost Based Optimizer as well <g>)
> Hurray for myths and their thoughtless perpetuation!
> /FGB
Well, there *is* a risk of getting queries with horrible execution plans. So, even if it's ROTten, I'd like some proof it won't harm, else no views over views as a ROT. And by proof, I'd like to see explain plan, etc.
Frank van Bortel
Received on Mon Feb 21 2005 - 04:35:20 CST

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