On 4/19/19 11:32 AM, Ken Tanzer wrote:
On Fri, Apr 19, 2019 at 11:20 AM Adrian Klaver
<adrian.klaver@xxxxxxxxxxx <mailto:adrian.klaver@xxxxxxxxxxx>> wrote:
On 4/19/19 11:14 AM, Rich Shepard wrote:
> On Fri, 19 Apr 2019, Adrian Klaver wrote:
>
>> If it is working for you now I see no reason to switch.
>
> Adrian,
>
> It does work. I just learned about the SQL identity type and want
to learn
> when it's most appropriate to use. The databases I develop all
work with
> integers as primary keys and reading about the type didn't
clarify (for me)
> when it should be used.
Mainly for folks that want cross database SQL compliance. It is not a
type so much as a way of specifying an auto-increment column.
It also sounds like it has advantages in terms of tying your sequence
directly to the column. If you drop a serial column, it doesn't drop
the sequence.
Misread your post the first time still:
create table serial_test(id serial, fld_1 text);
CREATE TABLE
test=> \d serial_test
Table "public.serial_test"
Column | Type | Collation | Nullable | Default
--------+---------+-----------+----------+-----------------------------------------
id | integer | | not null |
nextval('serial_test_id_seq'::regclass)
fld_1 | text | | |
test=> alter table serial_test drop column id;
ALTER TABLE
test=> \d serial_test
Table "public.serial_test"
Column | Type | Collation | Nullable | Default
--------+------+-----------+----------+---------
fld_1 | text | | |
test=> select * from serial_test_id_seq ;
ERROR: relation "serial_test_id_seq" does not exist
LINE 1: select * from serial_test_id_seq ;
Once I've upgraded to 10+, I might look at converting my existing serial
columns. Peter Eisentraut wrote a good piece(1) on identity columns,
including a function for converting existing serial columns. I've
copied the function below, but had two questions about it:
1) Would the function as written also reassign ownership to that table
column? (I see the update to pg_depend and pg_attribute, but don't know
enough about them to know if that changes ownership)
2) Would one have to be a superuser to do this?
Thanks,
Ken
--
Adrian Klaver
adrian.klaver@xxxxxxxxxxx
