Обсуждение: How to see the definition of an existing table?

Is there any command or query to see the definition of an existing table,
like which is the primary key, which is not null etc.

Thanks!

--Ke

Within psql you can do commands like 
\d <tablename>
to learn rudimentary information about 
a table. 

Try this to learn more sophisticated information 

select u.usename, t.typname, a.attname, a.atttypid, a.attlen, a.attnotnull, a.attnum 
from pg_user u, pg_type t, pg_attribute a 
where u.usesysid = t.typowner 
and t.typrelid = a.attrelid and t.typtype = 'c' and t.typname = 'pg_attribute' 

where 'pg_attribute' should be replaced by the table's name you 
are interested in. 

Unfortunately, I don't know nothing about how to find the primary key 
in a table definition. 
But go for the PostgreSQL documentation - Chapter System Catalogs - 
this should give you at least an idea which system catalog may 
deliver the information. 

Regards, Christoph 

On Mon, 17 Sep 2001 14:51:52 +0000 (UTC), ke wang <kw68@cornell.edu> wrote:
> Is there any command or query to see the definition of an existing table,
> like which is the primary key, which is not null etc.
> 

In psql:
\d tablename

to see what the exact query is, start psql with the -E flag:
psql -E
\d tablename