Titta på följande kommandon (särskilt det kommenterade blocket).
DROP TABLE foo;
DROP TABLE bar;
CREATE TABLE foo (a int, b text);
CREATE TABLE bar (a serial, b text);
INSERT INTO foo (a, b) SELECT i, 'foo ' || i::text FROM generate_series(1, 5) i;
INSERT INTO bar (b) SELECT 'bar ' || i::text FROM generate_series(1, 5) i;
-- blocks of commands to turn foo into bar
CREATE SEQUENCE foo_a_seq;
ALTER TABLE foo ALTER COLUMN a SET DEFAULT nextval('foo_a_seq');
ALTER TABLE foo ALTER COLUMN a SET NOT NULL;
ALTER SEQUENCE foo_a_seq OWNED BY foo.a; -- 8.2 or later
SELECT MAX(a) FROM foo;
SELECT setval('foo_a_seq', 5); -- replace 5 by SELECT MAX result
INSERT INTO foo (b) VALUES('teste');
INSERT INTO bar (b) VALUES('teste');
SELECT * FROM foo;
SELECT * FROM bar;