Postgresql Altering Table

Is it possible to alter a table to a开发者_如何学Cdd a new column and make that column a foreign key to another table in a single command in Postgresql? "alter table x add column y id references z(id)" doesn't seem to work as I had hoped.

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You can do it. What is "y id"? May be

alter table x add column y int references z(id)

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BEGIN
ALTER TABLE ... ADD COLUMN ...
ALTER TABLE ... ADD CONSTRAINT ...
COMMIT

You can't convince me it's not a single command :).