Hi there,
I am trying to add another primary key to an existing table with two other primary keys. I got the following error when I tried this command:
alter table extprobe2tissue ADD primary key (expid);
ERROR: multiple primary keys for table "extprobe2tissue" are not allowed
The details of the extprobe2tissue table is:
\d extprobe2tissue;
Table "public.extprobe2tissue"
Column | Type | Modifiers
-------------+------------------------+-----------
probeid | integer | not null
tissueid | integer | not null
value | double precision | not null
entrydate | date | not null
description | character varying(200) |
qval | double precision |
expid | integer | not null
Indexes:
"extprobe2tissue_pkey" PRIMARY KEY, btree (probeid, tissueid)
"extprobe2tissue_probeid" btree (probeid)
"extprobe2tissue_tissueid" btree (tissueid)
Foreign-key constraints:
"extprobe2tissue_tissueid_fkey" FOREIGN KEY (tissueid) REFERENCES tissue(tissueid)
"extprobe2tissue_probeid_fkey" FOREIGN KEY (probeid) REFERENCES extprobe(probeid)
Any suggestion would be much appreciated.
Thanks!