Re: CHECK col A not NULL if col B='x'

Hello again,


Martin Marques wrote:

> El Mar 28 Sep 2004 11:02, T E Schmitz escribió:
> 
>>Is it possible to set up a table CHECK, which ensures that column A is
>>NOT NULL if column B = 'x' ?
> 
> 
> CONSTRAINT somename CHECK (B <> 'x' OR A IS NOT NULL)

I noticed a table constraint can be added via ALTER TABLE. Is it correct 
that a column constraint cannot be added via the ALTER TABLE other than 
by dropping and adding the column? (I am using psql 7.4.2.)

-- 


Regards/Gruß,

Tarlika Elisabeth Schmitz