On 05/03/2016 02:27 PM, drum.lucas@xxxxxxxxx wrote:
On 4 May 2016 at 01:18, Melvin Davidson <melvin6925@xxxxxxxxx
<mailto:melvin6925@xxxxxxxxx>> wrote:
On Tue, May 3, 2016 at 1:21 AM, David G. Johnston
<david.g.johnston@xxxxxxxxx <mailto:david.g.johnston@xxxxxxxxx>> wrote:
Well.. I don't need to add a constraint if I already have a
default value, that's right...
Wrong
David J.
What you need is a TRIGGER function & TRIGGER that will select and
assign the next users_code based on company_id.
I'm not going to write the whole thing for you, but here is part of
the trigger function logic.
eg: IF NEW.company_id = 1 THEN
NEW.users_code = NEXTVAL(c1_users_code_seq);
ELSEIF NEW.company.id <http://NEW.company.id> = 2 THEN
NEW.users_code = NEXTVAL(c2_users_code_seq);
ELSEIF NEW.company.id <http://NEW.company.id> = 3 THEN
NEW.users_code = NEXTVAL(c3_users_code_seq);
...
...
ELSE
< something bad happened because NEW.company_id was
not valid ?
END IF;
Do I have to have one sequence peer company_id ? There will be
thousands.. isn't there a better way to do that?
A sequence just keeps on incrementing. If you want a gapless sequence
for each company that each increment independently of each other then
yes you will need a separate sequence for each.
For an alternate strategy see this related thread:
http://www.postgresql.org/message-id/2926B083-33C9-4648-8635-BC293C70ED45@xxxxxxxxxxxxxx
in particular this link from the thread:
http://www.postgresql.org/message-id/44E376F6.7010802@xxxxxxxxxxxxxxxx
Seriously, get yourself the books I have recommended and study them
BEFORE you continue attempting to design your database.
You need a firm understanding of logical design & flow, otherwise
you will be wasting your time.
That's what I'm doing.. Studying.. asking for some help to get a better
understand.... isn't this the purpose of this mail list?
--
Adrian Klaver
adrian.klaver@xxxxxxxxxxx
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