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Re: Converting to identity columns with domains on PK columns

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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)


Further thinking pointed up the peril of the above. Your field is defined as integer and per my previous post a sequence without an AS data_type will be bigint. At some point the sequence is going to start trying to set nextval() to a number your field cannot handle. If you go that route you will need to do something like:

create sequence id_seq AS integer owned by mytable.id;


--
Adrian Klaver
adrian.klaver@xxxxxxxxxxx





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