Re: 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

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