On 7/4/19 1:27 PM, Adrian Klaver wrote:
On 7/4/19 1:03 PM, PegoraroF10 wrote:
ok, thanks for the explanation but ... I cannot add a field and move
data,
constraints, triggers, identity to it because my pk field will be
repositioned to the last field on that table and I have lots of other
codes
which point to pk as the first field on every table.
I stay away from using the index position of field for this reason.
So, there is a way to convert that field to a identity field ?
See my second option in previous post.
Or, old school identity column:):
create sequence id_seq owned by mytable.id;
alter table mytable alter column id set default nextval('id_seq');
\d mytable
Table "public.mytable"
Column | Type | Collation | Nullable | Default
-------------+------+-----------+----------+-----------------------------
id | i32 | | not null | nextval('id_seq'::regclass)
description | t50 | | |
Indexes:
"mytable_pkey" PRIMARY KEY, btree (id)
I know this worked, but then I got to wondering why?
Found the answer in sequence.c(init_params) in the if (as_type != NULL)
section. When creating a sequence you can specify AS data_type as long
as the type is one of smallint, integer or bigint. If data_type is not
specified then the default is bigint. If I am following correctly in
tablecommands.c when you create an IDENTITY column it uses the type it
gets from the column for the AS data_type. In your case that would be a
domain type which is != to the base types above.
--
Adrian Klaver
adrian.klaver@xxxxxxxxxxx
