Re: In-place conversion of type bool

Hi Tom,

On Wed, 2008-08-13 at 21:27 -0400, Tom Lane wrote:
> "Joost Kraaijeveld" <J(dot)Kraaijeveld(at)Askesis(dot)nl> writes:
> > The database says that it's bool implementation is char(1), just as
> > PostgreSQL does. I can copy te data OK, but I would like to change the
> > actual type of the column from char(1) to bool. Is that possible without
> > copying the column to a temporary column, dropping the old column and
> > renaming the temporary columns to the old column?
>
> ALTER TABLE ... ALTER COLUMN TYPE might help you. Use the USING clause
> if you need a non-default data conversion -- in this case it might look
> like USING (col = '1') or some such.

ALTER TABLE odbcdest ALTER COLUMN odbc_bool TYPE bool

gives:

ERROR: column "odbc_bool" cannot be cast to type "bool"

********** Error **********

ERROR: column "odbc_bool" cannot be cast to type "bool"
SQL state: 42804

>
> (This is probably not physically more efficient than making a temp
> table, however.)

Could you elaborate on this? I have tried something like this, but when
the column in question is a column that is used in foreign keys I am
forced to drop any foreign keys that point to this column. Which is quit
annoying on a 200 table database with lots of foreign keys.

TIA

--
Groeten,

Joost Kraaijeveld
Askesis B.V.
Molukkenstraat 14
6524NB Nijmegen
tel: 024-3888063 / 06-51855277
fax: 024-3608416
web: www.askesis.nl