Re: Table with Field Serial - Problem

On 10/31/2013 09:32 AM, David Johnston wrote:
> Adrian Klaver-3 wrote
>>> Table1
>>>    Column  |       Type        |                          Modifiers
>>> ----------+-------------------__+-----------------------------__------------------------------__--
>>>    id   | integer           | not null default
>>> nextval('test_table_id_fld___seq'::regclass)
>>>
>>>
>>> Table2
>>> Column  |       Type        |                      related
>>> ----------+-------------------__+-----------------------------__------------------------------__--
>>>    id_table1   | integer           |  FK of Table1.id
>>>    id_lang       | integer          |  FK of lang.id
>>> <http://lang.id>
>>>    name         |  varchar
>>>
>
> The PK for table 2 is composite: the serial key from table 1 + the language
> id.  The table 1 id has to be able to repeat since the same "entity" needs
> multiple translations.  Using a serial on table 2 is also possible but a
> separate issue and probably not worth adding since you need a unique index
> on (id_table1, id_lang) regardless.
>
> The question is why isn't there some kind of identifier on table 1 that
> gives you some idea of what the id/table record is for?

Exactly the id_table1 FK has no context, it is just a number generator,
so why make it separate? If want to just generate numbers why not just
use the sequence directly?

>
> David J.
>
>



--
Adrian Klaver
adrian.klaver@gmail.com