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.)
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Regards/Gruß,
Tarlika Elisabeth Schmitz
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