Re: Finding column using SQL query.

Buddy. This is what I was looking out.

Thanks,
Rajan

-----Original Message-----
From: email@juergen-cappel.de [mailto:email@juergen-cappel.de]
Sent: Wednesday, February 09, 2005 5:26 PM
To: Rajan Bhide
Cc: pgsql-novice@postgresql.org
Subject: RE: [NOVICE] Finding column using SQL query.



Here is what I do in my application (slightly reduced for clarity):

    select pg_class.relname,pg_type.typname,pg_attribute.attname
    from pg_class,pg_type,pg_attribute
    where pg_attribute.attrelid=pg_class.oid
    and pg_attribute.atttypid=pg_type.oid
    and pg_class.relname = 'yourtable'

Also you may look at the reference of attrelid on this page:

http://www.postgresql.org/docs/8.0/interactive/catalog-pg-attribute.html


HTH, Jürgen




Rajan Bhide <rbhide@starentnetworks.com> schrieb am 09.02.2005,
12:43:28:
> >>pg_attribute.attrelid=pg_class.oid
> I am not able to find any attribute name 'oid' for pg_class. Is this
> new in 8.0? Can you construct a query to explain this?
>
> Thanks,
> Rajan
>
>
> -----Original Message-----
> From: email@juergen-cappel.de [mailto:email@juergen-cappel.de]
> Sent: Wednesday, February 09, 2005 5:02 PM
> To: Rajan Bhide
> Cc: pgsql-novice@postgresql.org
> Subject: Re: RE: [NOVICE] Finding column using SQL query.
>
>
>
> You have to link like this:
>
>     pg_attribute.attrelid=pg_class.oid
>
> and to find the datatye of an attribute:
>
>     pg_attribute.atttypid=pg_type.oid
>
>
>
> HTH, Jürgen
>
>
>
>
> Rajan Bhide  schrieb am 09.02.2005,
> 12:10:54:
> > I tried finding relation between pg_attribute and pg_class but seems
> > there is no common key between these two table.
> >
> > select * from pg_attribute where attrelid = (select reltype from
> > pg_class  where relname = 'mytablename';  attrelid | attname |
> > atttypid | attstattarget | attlen | attnum | attndims | at
> > tcacheoff | atttypmod | attbyval | attstorage | attisset | attalign |
> > attnotnull
> >  | atthasdef
> > ----------+---------+----------+---------------+--------+--------+--
> > ----------+---------+----------+---------------+--------+--------+--
> > ----------+---------+----------+---------------+--------+--------+--
> > ----+---
> > ----------+-----------+----------+------------+----------+----------+-
> > ----------+-----------+----------+------------+----------+----------+-
> > ----------+-----------+----------+------------+----------+----------+-
> > --------
> > -+-----------
> > (0 rows)
> >
> >
> > So this is not solving my problem.
> > Am I missing somethg or there is some other way to find out? Plz
> > comment.
> >
> > Thanks,
> > Rajan
> >
> > -----Original Message-----
> > From: email@juergen-cappel.de [mailto:email@juergen-cappel.de]
> > Sent: Wednesday, February 09, 2005 3:38 PM
> > To: Rajan Bhide
> > Cc: pgsql-novice@postgresql.org
> > Subject: Re: [NOVICE] Finding column using SQL query.
> >
> >
> >
> > Take a look at the system catalogs:
> >
> > http://www.postgresql.org/docs/8.0/interactive/catalogs.html
> >
> > HTH
> >
> >
> >
> > Rajan Bhide  schrieb am 09.02.2005,
> > 10:56:20:
> > > Hi,
> > >
> > > Is there any way to find whether a particular column exists in the
> > > table or not based on the column name using sql query? I have a
> > > requirement where I need to find whether a column exists in the
> > > table or not using SQL query.
> > >
> > > Thanks,
> > > Rajan
> > >
> > > ---------------------------(end of
> > > broadcast)---------------------------
> > > TIP 9: the planner will ignore your desire to choose an index scan
> > > if
> > your
> > >       joining column's datatypes do not match