Thread: Where's The Primary Key?
Hi, I'm new to Postgresql and having trouble finding some familiar ground. I'm on Redhat 7.2, and using Postgresql 7.1.3 (I think). Postgresql was installed with the operating system with no "help" on my part. I've created a simple table as shown below and can't find any indication that the primary key was created. I would expect the \d meta-command to show the primary key. (pgaccess also indicates that there is no primary key defined.) I've tried this with a column constraint, a table constraint, with and without the constraint name, and a few other variants. All had the same results. Is the key really there? Shouldn't I see it? Am I doing it wrong or thinking about it wrong? I'd appreciate any help to get me kick-started. db01=> CREATE TABLE junk_t ( db01(> idx int CONSTRAINT junk_idx PRIMARY KEY, db01(> dat int db01(> ); NOTICE: CREATE TABLE/PRIMARY KEY will create implicit index 'junk_idx' for table 'junk_t' CREATE db01=> \d junk_t Table "junk_t" Attribute | Type | Modifier -----------+---------+---------- idx | integer | not null dat | integer | Index: junk_idx db01=>
Am Fre, 2003-07-25 um 09.13 schrieb Jim Louis: > Table "junk_t" > Attribute | Type | Modifier > -----------+---------+---------- > idx | integer | not null > dat | integer | > Index: junk_idx \d junk_idx apart from that, it's much easier just to do: ... idx int PRIMARY KEY, ... Just leave the naming of the index to postgresql. FYI: You may also want to use SERIAL instead of INT. It creates INT but with (auto-filled) serial numbers (auto increment). hth -- e-Trolley Sayegh & John, Nabil Sayegh Tel.: 0700 etrolley /// 0700 38765539 Fax.: +49 69 8299381-8 PGP : http://www.e-trolley.de
> db01=> \d junk_t > Table "junk_t" > Attribute | Type | Modifier > -----------+---------+---------- > idx | integer | not null > dat | integer | > Index: junk_idx Primary key is the combination of unique index + not null. In your case, both are listed. For further details refer pg_indexes system view. regards, bhuvaneswaran
On Mon, Jul 28, 2003 at 09:26:33 +0530, > > Primary key is the combination of unique index + not null. In your case, > both are listed. For further details refer pg_indexes system view. That isn't the whole story. The primary key of a table is also a default for foreign keys. There can be several columns that have a unique index and a not null constraint, but there can be only one primary key. (The primary key can also be multicolumn.)