adding a primary key column to a temporary table fails (v7.4.3)

Hi,

I guess this might not be the appropriate thing to be happening:

# select version();
version
---------------------------------------------------------------------
PostgreSQL 7.4.3 on i686-pc-linux-gnu, compiled by GCC egcs-2.91.66
(1 row)

(verify whether temporary tables do support primary keys)
# create temp table f_test (id int primary key, value varchar(20));
NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "f_test_pkey"
for table "f_test"
CREATE TABLE

# drop table f_test;
DROP TABLE

(now create it without the primary key)
# create temp table f_test (value varchar(20));
CREATE TABLE

(and add the column afterwards)
# alter table f_test add column id int primary key;
NOTICE: ALTER TABLE / ADD PRIMARY KEY will create implicit index
"f_test_pkey" for table "f_test"
ERROR: adding NOT NULL columns is not implemented
HINT: Add the column, then use ALTER TABLE SET NOT NULL.

By the way, I noticed that the todo-list does not mention 'alter table alter
column set/drop primary key'. I'm wondering whether it should?

Ratio:
I was trying to avoid repeating complex create temp table statements by doing
stuff like 'create temp table <foo> as select * from <bar> where false'
instead. But since the resulting table doesn't have any indexes on it and one
of the libraries I use actually expects a 'real' primary key to be available,
I was looking for ways to get to a temporary table with a copied structure
AND a primary key.

--
Best,

Frank.