[SQL] how to add primary key to existing table with multiple primary keys

[Daniel Joo]

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!  

[SQL] viewing the description of tables from python DB-API

[Daniel Joo]

Hi all,

 

Is there a way to view the list of all tables from python
(or any other languages for that matter) DB-API?  What I’m looking for is
a command similar to the meta-command ‘\d’ that works with the psql
client.  

 

Thanks very much!

 

Dan