Re: how to view the content of schema pg_catalog?

On May 8, 2007, at 1:33 PM, Fei Liu wrote:
> Jim C. Nasby wrote:
>> Please include the list in your replies so that others can learn.
>>
>> On Mon, May 07, 2007 at 09:35:10AM -0400, Fei Liu wrote:
>>
>>> Jim Nasby wrote:
>>>
>>>> On Apr 25, 2007, at 4:37 PM, Fei Liu wrote:
>>>>
>>>>> I couldn't find anything in the postgresql manual as how to
>>>>> view its content. SELECT does not seem to work.
>>>>>
>>>> What's the exact command and error message?
>>>>
>>> netilla=#  \dn
>>>        List of schemas
>>>        Name        |  Owner
>>> --------------------+----------
>>> information_schema | postgres
>>> pg_catalog         | postgres
>>> pg_toast           | postgres
>>> public             | postgres
>>> (4 rows)
>>>
>>> netilla=# select * from pg_catalog;
>>> ERROR:  relation "pg_catalog" does not exist
>>>
>>
>> That would be because pg_catalog is a schema; you can't select
>> from it.
>> If you want to see what's in there, use \dS.
>>
> Thanks, \dS works ( it does not take an argument). Is there a
> programtic way for me to see this from either Perl or C? Does pgsql
> export APIs to check schema content?

Sure, read about the structure of the catalog tables in the docs and
query them directly. Starting psql with the -E option and running
various \d commands might prove enlightening as well. You can also
take a look at the definition of stuff in information_schema or the
newsysviews project on pgFoundry.
--
Jim Nasby                                            jim@nasby.net
EnterpriseDB      http://enterprisedb.com      512.569.9461 (cell)