Thread: How to get tabloid

List,

I have a temporary table and I need to get the tableoid from the interface.
The table may not have any data in it so something like SELECT tableoid FROM
tmp_table LIMIT 1, returns zero when there is no data in the table. I know
that you can get information like this from the system catalogs but don't
know how to join them to accomplish this. Is there a diagram available which
shows the system catalog relationships and does anyone have a simple sql
string that will give me the tableoid of a given table.

TIA

--

To answer at least part of my own question:

SELECT oid FROM pg_class WHERE relname = 'cust';

apparently gives the tableoid.

On Friday 30 September 2005 06:25 am, Terry Lee Tucker saith:
> List,
>
> I have a temporary table and I need to get the tableoid from the interface.
> The table may not have any data in it so something like SELECT tableoid
> FROM tmp_table LIMIT 1, returns zero when there is no data in the table. I
> know that you can get information like this from the system catalogs but
> don't know how to join them to accomplish this. Is there a diagram
> available which shows the system catalog relationships and does anyone have
> a simple sql string that will give me the tableoid of a given table.
>
> TIA
>
> --
>
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>
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On Fri, Sep 30, 2005 at 06:53:25AM -0400, Terry Lee Tucker wrote:
> To answer at least part of my own question:
>
> SELECT oid FROM pg_class WHERE relname = 'cust';
>
> apparently gives the tableoid.

This query should restrict its results with pg_table_is_visible() --
otherwise you might get the wrong oid if the temporary table has
the same name as a non-temporary table, or if multiple sessions
have temporary tables with the same name.

Here's another way:

SELECT 'cust'::regclass::oid;

--
Michael Fuhr

Thank you Michael. I did see the behavior you mentioned when two sessions had
temp tables with the same name. Your way is much better.

On Friday 30 September 2005 01:30 pm, Michael Fuhr saith:
> On Fri, Sep 30, 2005 at 06:53:25AM -0400, Terry Lee Tucker wrote:
> > To answer at least part of my own question:
> >
> > SELECT oid FROM pg_class WHERE relname = 'cust';
> >
> > apparently gives the tableoid.
>
> This query should restrict its results with pg_table_is_visible() --
> otherwise you might get the wrong oid if the temporary table has
> the same name as a non-temporary table, or if multiple sessions
> have temporary tables with the same name.
>
> Here's another way:
>
> SELECT 'cust'::regclass::oid;
>
> --
> Michael Fuhr

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