Re: How to check: is some key referenced from sometable

Hello, Bruno.

You wrote 9 08 2003, 18:08:09:

BWI> On Mon, Aug 04, 2003 at 11:17:56 +0300,
BWI>   evl@my-mail.com.ua wrote:
>> Please help.
>> 
>> Need a boolean function which returns true if given key in table is
>> referensed from another table(s).

BWI> Use "exists" with a subselect. Something like:
BWI> select exists(select 1 from table where table.key = 'value');

Thanx for advice, but way I know and it can't be used.That's why I've got too many and/or too big tables from which
such key is referenced. I mean (in some simplified way):
table A (             -- main table A id SERIAL, PRIMARY KEY(id));
tableBxx (            -- a lot of tables which got a.id as FOREIGN KEY ...                  -- too much to check 'em
allwith EXISTS queries a_id int4 REFERENCES a(id),      -- without significant perfomance loss ...);
 
So I need:  "silent delete" - i.e. when trying to DELETE row from A I'll not fall out with "$1 referential integrity
violation- key in A still referenced from Bxx", but silently doesn't delete row ('cause run it from function and need
functionto executes farther after delete);  "something to check reference" - system (potgresql) is very quickly
realizesthat key is referenced from another table, maybe this information may be accessed through some system
relations,or so?
 
Thanx for attention. 
-- 
Best regards,             eVl