Shavonne Marietta Wijesinghe wrote:
Even though n_gen is defined as a serial I can't let it handle the
progressive key by its self since there is the need that some records
should have the same value.
Of course you can - the default is only provided if you don't provide
your own.
That's why i use 3 primary keys.
No, you're not. By definition you can only have one primary key. You are
using a 3-column primary key.
A | B | C
---+---+---
1 | 1 | 1
2 | 1 | 3
2 | 2 | 3
2 | 3 | 3
3 | 1 | 2
3 | 2 | 2
4 | 1 | 1
The 3 keys A, B, C are defined as Serial and Primay Keys
You don't have 3 keys, you have 3 columns and one primary key (A,B,C).
I'm not clear why B and C are serial - I don't see what that gets you.
Anyway the other suggestion, Blocking the second user from reading the
db. So for the second user I could give A temp key something like 0 and
then do a select before the submit and change the value.
But how is it possible to know if some other user is reading the db??
Don't try. If you want to insert some rows with a new value for A do
something like:
INSERT INTO my_shevi (a,b,c) VALUES (DEFAULT, 1, 1);
or
INSERT INTO my_shevi (a,b,c) VALUES (nextval(<sequence-name-here>, 1, 1);
INSERT INTO my_shevi (a,b,c) VALUES (currval(<sequence-name-here>), 1, 2);
INSERT INTO my_shevi (a,b,c) VALUES (currval(<sequence-name-here>), 1, 3);
etc.
Relevant parts of the manual (in 8.3 anyway):
9.15. Sequence Manipulation Functions
9.22. System Information Functions
The second chapter is for pg_get_serial_sequence() which might be useful
if you need to do this a lot.
Oh - and please try trimming unwanted parts of the message when you
reply. There was 100 unnecessary lines below here.
--
Richard Huxton
Archonet Ltd
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