Thanks for the replies, I have one question regarding this comment...
"You also need to add a DEFAULT expression and optionallymake the sequence owned by the column:" What difference does it make if a table "owns" a sequence of not?...does this contraint the use of the sequence to ONLY that one table? The sequence will only be used to auto-increment the id column in order to have an automatic primary key. Could I then somehow use the sequence for all tables which need this? yours, Rob ________________________________ Von: Boszormenyi Zoltan <z...@cybertec.at> An: pgsql-general@postgresql.org Gesendet: 13:43 Dienstag, 4.Oktober 2011 Betreff: Re: [GENERAL] auto-increment column 2011-10-04 13:30 keltezéssel, Robert Buckley írta: Hi, > > >I have a column in a table called hist_id with the datatype "integer". When I >created the table I assigned this column the primary key constraint but didn´t >make it an auto-increment column. > > >How could I do this to an the already existing column? > > >I have created the sequence with the following command but don´t know how to >change the existing column to auto-increment. > > > > >$ create sequence hist_id_seq; You also need to add a DEFAULT expression and optionally make the sequence owned by the column: ALTER TABLE tablename ALTER COLUMN hist_id SET DEFAULT nextval('hist_id_seq'); ALTER SEQUENCE hist_id_seq OWNED BY tablename.hist_id; The "ALTER SEQUENCE ... OWNED BY ..." will make the sequence automatically dropped if this column or table is dropped. > >thanks for any help, > > >Rob -- ---------------------------------- Zoltán Böszörményi Cybertec Schönig & Schönig GmbH Gröhrmühlgasse 26 A-2700 Wiener Neustadt, Austria Web: http://www.postgresql-support.de http://www.postgresql.at/