Question

I would like to drop the sequence used in table and the table itself in one statement using CASCADE, but I’m getting NOTICE and table is not dropped. For example:

CREATE SEQUENCE seq1;
CREATE TABLE t1 (f1 INT NOT NULL DEFAULT nextval('seq1'));

And then when I do:

DROP SEQUENCE seq1 CASCADE;

I get following message, and the table is not dropped:

NOTICE:  drop cascades to default for table t1 column f1

I’m definitely doing something wrong but these are my very first steps in PostgreSQL.

Answer 1

The table is never a depending object of an associated sequence and is never dropped by:

DROP SEQUENCE ... CASCADE;

Only a column DEFAULT drawing from the sequence "depends" on the sequence and is set to NULL if the sequence is deleted with CASCADE.

It’s the other way round: if the sequence is owned by a table column it is dropped with:

DROP TABLE f1 CASCADE;

For a sequence to be owned by a table column you can either use the serial type, or ALTER an existing sequence:

ALTER SEQUENCE seq1 OWNED BY t1.f1;