On Fri, Jan 13, 2006 at 09:02:17AM +0100, Nico Grubert wrote: > After I truncated tblperson I supposed that the Id will start with 1 > again if I insert a new record into tblperson. I thought, truncating the > table tblperson will also reset its sequence "tblperson_id_seq"!? Am I > wrong? Yes, that's wrong. Deleting from or truncating a table doesn't modify any sequences. > After that, I tried to set the sequence back to 1 since I cannot set the > sequence to 0 using setval() (error: value 0 is out of bounds for > sequence). Unfortunately, setting the sequence back to 1 will start with > id = 2 Not if you use the three-argument form of setval() with the third argument set to false or if you use ALTER SEQUENCE. http://www.postgresql.org/docs/8.0/interactive/functions-sequence.html http://www.postgresql.org/docs/8.0/interactive/sql-altersequence.html test=> CREATE SEQUENCE foo; CREATE SEQUENCE test=> SELECT nextval('foo'); nextval --------- 1 (1 row) test=> SELECT nextval('foo'); nextval --------- 2 (1 row) test=> SELECT setval('foo', 1, false); setval -------- 1 (1 row) test=> SELECT nextval('foo'); nextval --------- 1 (1 row) test=> ALTER SEQUENCE foo RESTART WITH 1; ALTER SEQUENCE test=> SELECT nextval('foo'); nextval --------- 1 (1 row) -- Michael Fuhr
