- Архив списков рассылки pgsql-sql

I have a reference which is guaranteed not to have a valid reference 
(preferably NULL) until it is processed later. How can I defer a 
reference entry so that both NULL and an actual reference are valid in 
the reference field? The processing which I speak of takes place later 
and not in the same transaction (thus making DEFERRABLE useless, 
right?). A solution I thought of is to forget keys and just make it an 
INT8 since I am also guaranteed that its referenced item is never 
deleted. But certainly, there is a more reliable way to do it, right?In summary, what I want is
 field INT8 REFERENCES sometable NULL OK

or

field INT8 CHECK(SELECT id FROM someothertable WHERE field=id)

(can I do this? this allows NULL right?)

The rule is ref2 can either be a valid reference or NULL.
CREATE TABLE thetable(ref2 INT8 REFERENCES someothertable,...
);

Thanks for any help.><><><><><><><><><
AgentM
agentm@cmu.edu