Which record in the parent table would the foreign key refer to if there were
multiple (non unique) records with the same value in the referenced table?
Ed L. wrote:
> On Wednesday April 2 2003 3:31, Ed L. wrote:
>
>>Well, I've stared at this little riddle for long enough. Anyone see a
>>mistake?
>>
>>CREATE TABLE person (
>> id SERIAL,
>> name VARCHAR NOT NULL
>>);
>>
>>CREATE TABLE session (
>> id SERIAL,
>> person_id INTEGER NOT NULL,
>> FOREIGN KEY (person_id) REFERENCES person (id)
>>);
>>
>>psql:test.sql:12: ERROR: UNIQUE constraint matching given keys for
>>referenced table "person" not found
>
>
> Ah. I was wondering why this didn't work anymore when it worked in 7.1. I
> guess the change in SERIAL semantics where the unique index is no longer
> created is what causes the problem. If I used PRIMARY KEY or create a
> unique index manually on person.id, it works fine. It seems odd that one
> cannot have a foreign key to a non-indexed column in another table.
>
> Ed
>
>
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