On Tue, 2003-05-13 at 01:18, marshall@perilith.com wrote:
> Hello,
>
> This has been asked before, but the responses weren't clear enough
> for me to understand.
>
> I have a table `mytable' with an attribute `mycol' of datatype char(4) and
> I'd like to change it to varchar(20). Mycol is populated by two values -
> NULLs and four element chars. What I've tried thusfar:
>
> db=> ALTER TABLE mytable ADD COLUMN mycol_new VARCHAR(20);
> ALTER TABLE
> db=> INSERT INTO mytable (mycol_new) SELECT mycol FROM mytable;
> ERROR: ExecInsert: Fail to add null value in not null attribute fqdn
>
> The `fqdn' attribute is another column in mytable.
>
> So is it the case that INSERT doesn't like inserting NULL values? Is
> there another way to do this?
INSERT inserts new rows and all constraints for the row must be
satisfied; use UPDATE to alter existing rows.
UPDATE mytable SET mycol_new = mycol;
(no WHERE clause, because you want to change every row).
--
Oliver Elphick Oliver.Elphick@lfix.co.uk
Isle of Wight, UK http://www.lfix.co.uk/oliver
GPG: 1024D/3E1D0C1C: CA12 09E0 E8D5 8870 5839 932A 614D 4C34 3E1D 0C1C
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