Thread: all non-PK columns from information schema

I'd  like to select all column names for a specific table except those
that are part of the PK.

I know I need to somehow join information_schema.columns,
key_column_usage and table_constraints but how?

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Best Regards,
Tarlika Elisabeth Schmitz

On Tue, 15 Nov 2011 09:26:35 -0600
Mike Blackwell <mike.blackwell@rrd.com> wrote:

>On Tue, Nov 15, 2011 at 02:59, Tarlika Elisabeth Schmitz <
>postgresql6@numerixtechnology.de> wrote:
>
>> I'd  like to select all column names for a specific table except
>> those that are part of the PK.
>> --
>> Tarlika Elisabeth Schmitz
>>
>I'd probably use the system catalogs.  See
>http://www.postgresql.org/docs/9.1/interactive/catalogs.html
>
>You could do something along the lines of:
>
>select attname from pg_class t
>join pg_attribute on (attrelid = t.oid)
>where attnum > 0
>and not exists (select 1 from pg_constraint where conrelid = t.oid and
>attnum = any(conkey) and contype = 'p')
>and relname = 'table_of_interest'
>__________________________________________________________________________________
>*Mike Blackwell | Technical Analyst, Distribution Services/Rollout

Thanks for the reply, Mike.
Interesting. I have previously used the information_schema for similar
queries.

What are the pros and cons for using either pg_catalog or
information_schema?

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Best Regards,
Tarlika Elisabeth Schmitz

On Tue, Nov 15, 2011 at 8:00 AM, Tarlika Elisabeth Schmitz
<postgresql6@numerixtechnology.de> wrote:
> Interesting. I have previously used the information_schema for similar
> queries.
>
> What are the pros and cons for using either pg_catalog or
> information_schema?

My understanding is that pg_catalog tables and views *can* change
between major releases while the information_schema is expected to be
more stable between major releases.

Applications that depend upon the information_schema rather than
pg_catalog are less likely to break when the PostgreSQL server is
upgraded.

--
Regards,
Richard Broersma Jr.