Re: Stored procedures and "pseudo" fields..
От | Scott Marlowe |
---|---|
Тема | Re: Stored procedures and "pseudo" fields.. |
Дата | |
Msg-id | 1090338306.709.25.camel@localhost.localdomain обсуждение исходный текст |
Ответ на | Stored procedures and "pseudo" fields.. (Lars Erik Thorsplass <thorsplass@gmail.com>) |
Список | pgsql-general |
On Tue, 2004-07-20 at 04:43, Lars Erik Thorsplass wrote: > I have recently ventured into the exciting world of stored procedures, > but I have now become lost. > > Background: > > Am currently working on access control in a web application. My goal > is to process access control on the SQL level. This way if a row is in > the result set, you have access to it, if not, you dont. > > > Problem: > > My stored procedure "acl_check()" takes two integers as parameters. > Param1 is the object id to check acl on, Param 2 is the object id of > the user currently using the system. The procedure returns a positive > numer (1 or 3 ) if you have some kind of access to the object. As one > might understand I want the returned value from the acl_check() > procedure to be a part of the result set. > > Kinda like this: > > SELECT *, acl_check( objects.obid, <user_id> ) AS mode FROM objects > WHERE mode > 0; Here's the problem. In order to do the select, the query first needs to run the where clause. I.e.: select a as test from table where a > 50; works, but select a as test from table where test > 50; fails. The reason is that when the where clause fires first, there IS no test yet, as it hasn't been materialized. what you need to do is: select custom_function(a,b) from table where custom_function(a,b) > 0;
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