[EMAIL PROTECTED] wrote:
Quoting Daryl Richter <[EMAIL PROTECTED]>:
[EMAIL PROTECTED] wrote:
> Quoting Daryl Richter <[EMAIL PROTECTED]>:
>> It's hard to say without knowing more precisely what you are trying to
>> model, but I think this push you in the right direction:
>>
> Okay, but references between (output/input) and ACTIVITY tables is 1
to N.
> OUTPUT/INPUT - 1
> to
> ACTIVITY - N.
> And not N to 1 how the example.
> Then the reference field need to be on "ACTIVITY (send/buy)" table.
>
Ahh, ok. In that case I reverse it like so:
-- This table hold everything in common for inputs/outputs
create table transfer(
id serial primary key
);
Yes, I think it was what I wanted.
And how I check if a register in "Transfer" table is only referenciable
by ONE
table (OR "output" OR "input")?? Would I create a Trigger like:
CREATE or REPLACE FUNCTION TG_output_check() RETURNS TRIGGER AS
$$
BEGIN
IF exists (select 1 from input where transfer_id=NEW.transfer_id) THEN
Raise Exception 'This activity (transfer) is alread setted to INPUT';
END IF;
RETURN NEW;
END;
$$ language 'plpgsql'; CREATE TRIGGER TG_output_check BEFORE INSERT or
UPDATE
on OUTPUT EXECUTE PROCEDURE TG_output_check();
CREATE or REP...--- and the some function to INPUT ---
Or is there another way to check it?
Thank you again.
Exactly, except for the small change that your trigger declaration needs
"for each row" as shown below:
CREATE TRIGGER TG_output_check BEFORE INSERT or UPDATE on output
for each row EXECUTE PROCEDURE TG_output_check();
--
Daryl
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