Re: A technical question about VIEWS

Olen wrote:
>
> NNOOR <Nnoor_at_cris.com> wrote in article
> <5hco8f$f85_at_chronicle.concentric.net>...
> >
> > I know what views are. I want to know how views handle queries which
> > run against them. Is the view first built and then user's query is
> > satisfied from the result set (ofcourse, when NOT running SELECT *), or
> > the view is built only for the records which also satisfy user's
> > query--i.e. dynamically changing it's query. Following example will
> > explain the question I am trying to ask...
> >
> > Lets say a view is built by joining x tables. And if the Select * is
> > run for the view then, say, it returns 10,000 rows. Now if a query is
> > run against the view with a selection criteria which will result in, say,
> > only 10 rows. How will Oracle handle this situation. Will it first create
> > the view with 10,000 rows and then run the user's query on the result
> > set or it will dynamically add the selection criteria to the view's
> > query so that a result set with only 10 records is built?
> >
> > I am trying to establish that how "expensive" the view operation is
> > for internal application development purposes...
> >
> > Thanks very much for your help!
> >
> > Regards,
> > Nasir (nnoor_at_cris.com)
>
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> The view's query is not dynamic, you are building an intermediate table. A
> view reacts like a subquery. It always
> returns the same solution set regardless of what else you specify in the
> query. So the answer is that Oracle will first create the view will 10,000
> rows. Then process the rest of the query against it.
>
> That's how I understand it.
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This question has been answered before, and your answer is completely wrong in almost every respect.

Please read earlier responses and please don't give answers like this. It is not helpful.

Chrysalis. Received on Mon Apr 14 1997 - 00:00:00 CDT