Re: A technical question about VIEWS

NNOOR wrote:
>
> 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)

"When you reference a view in a SQL statement, Oracle merges the statement that references the view with the query that defines the view, and then parses the merged statements in a shared SQL area and executes it."

Oracle7 Server Concepts Manual Chapter 5 Received on Thu Mar 27 1997 - 00:00:00 CST