Re: What is pragma restrict refrences

A copy of this was sent to Anurag <anurag_at_synergy-infotech.com> (if that email address didn't require changing) On Fri, 26 Nov 1999 03:51:49 -0800, you wrote:

>Hi,
>I have come across the statement pragma restrict refrences. what does
>that mean?
>

it is in the manuals but a short explaination is

• you can call PLSQL from sql (eg: select your_plsql_function from T)
• in order to call plsql from sql it must promise to NOT write to the database at the very least. (depending on the circumstances, it might have to NOT write to the package state -- package global variables, or it might not be able to READ the package state -- package global variables, or it might not be able to READ the database state)
• when you compile a package spec, you may want to tell us if a procedure WNDS = write no database state WNPS = write no package state RNDS = read no database state RNPS = read no package state

This is called the purity of a function/procedure. If a function is pure enough, it can be called from sql. If it is not, it cannot be. If you tell us a function is "WNDS, WNPS" via the pragma restrict_references directive but when we compile the body we discover otherwise the compilation fails.

• you do not (cannot) use this pragma for STANDALONE (non-packaged) procedures and functions. their purity is derived automagically at compile time for you.
• in oracle8i, it is not necessary to use this anymore. its figured out for you.

>Any help will be appreciated.
>
>Thanks
>Anurag
>
>also reply at
>anurag_at_synergy-infotech.com
>
>
>
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--
See http://osi.oracle.com/~tkyte/ for my columns 'Digging-in to Oracle8i'... Current article is "Part I of V, Autonomous Transactions" updated June 21'st  

Thomas Kyte                   tkyte_at_us.oracle.com
Oracle Service Industries     Reston, VA   USA

Opinions are mine and do not necessarily reflect those of Oracle Corporation Received on Fri Nov 26 1999 - 07:51:37 CST