[SQL] Add Constraint

[Sivagami .]

Hi all,
 
I am a newbie to Postgresql, but I am familiar with SQL. I am 
trying to add a constraint to my table using the ALTER TABLE command. The 
command goes like this :
 
ALTER TABLE USER_SIGNUP ADD 
CONSTRAINTP_USER_SIGNUP_USER_ID PRIMARY KEY(user_id);
 
But it is returning the error 
ERROR:  ALTER TABLE / ADD CONSTRAINT is not implemented 

 
Can anyone guide me in the right direction???
 
Thanks.
Shiva

[SQL] .

[Sivagami .]

Hi all,
 
 
I tried:SELECT * FROM 
DB1.MY_TABLE;from DB2 and it did not like the syntax.  I 
assume that you cannot select across database/schemas.Is this 
correct?
Shiva

[SQL] Foreign key constraint

[Sivagami .]

 

Hi,
 
I have a question. I tried adding a Foreign Key constraint to 
a table via the ALTER TABLE command. But the records in the table did not match 
with those in the Parent table. Now my Alter table command, instead of giving me 
an error of kind - 'records do not match',  has gone into a kind of 
Deadlock between the 2 tables. I am not able to select from the tables, nor 
delete them, nor drop them. If I try to do any of these, I get the error 
saying -
" Error :  RelationBuildTriggers: 2 record(s) not 
found for rel invoice"
 
How do I overcome this error. Any ideas will be greatly 
appreciated.
Thanks a lot in advance.
 
Shiva.