Re: serial as FK ?

On Mon, 28 Feb 2005, Richard Huxton wrote:

> Oleg Bartunov wrote:
>> Hi there,
>> 
>> what's wrong to use SERIAL as FK without explicit PRIMARY KEY or UNIQUE ?
>> 
>> qq=# create table t1( id serial);
>> NOTICE:  CREATE TABLE will create implicit sequence "t1_id_seq" for 
>> "serial" column "t1.id"
>> CREATE TABLE
>> qq=# create table t2( id2 int4 references t1(id));
>> ERROR:  there is no unique constraint matching given keys for referenced 
>> table "t1"
>> 
>> btw, Richard, I noticed this problem when looked into your example database
>> http://www.archonet.com/pgdocs/chap-exdb.html#EXAMPLE-TABLES
>
> Ah - IIRC there *was* nothing wrong with it when those notes were written 
> (and I need to update them, clearly). Back then SERIAL implied UNIQUE too, 
> but that was changed (in 7.3 I believe).

There are also some problems in examples. I think your notes are rather
useful.

>
>
    Regards,        Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
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