Thread: Distinguish view and table problem

On Fri, Dec 18, 2009 at 10:57 AM, suzhiyang <suzhiyang@gmail.com> wrote:
> Another question is that does postgres save the user's original query_string
> at anywhere(systable etc.)? If I want to save the sourceText in the
> systable, I could add a column to pg_class called query_string. How could I
> insert a line to pg_class or read a line from it?

pg_class wouldn't make much sense for this.  But you might be
interested in pg_stat_activity.

...Robert

"suzhiyang" <suzhiyang@gmail.com> writes:
> I just want to distinguish a view and a table while postgres execute
> exec_simple_query(). In the systable of pg_class, a view and a table
> has different relkind ('r' 'v'). But when I print the parsetree and
> the rewrite parsetree, I found that a view and a table has no
> character to distinguish because the structure Relation has no
> attribute called relkind.

See rel->rd_rel->relkind ...
        regards, tom lane

2009/12/19 Filip Rembiałkowski <plk.zuber@gmail.com>:
>
> W dniu 19 grudnia 2009 03:20 użytkownik suzhiyang <suzhiyang@gmail.com>
> napisał:
>>
>> Sorry, I've not describe my problem precisely.
>> I mean that  I want to get relkind or something from a systable by the
>> programm but not by sql.
>
> I don't understand how you can get data from table without using SQL. (maybe
> I'm just "too sql")
>

i think he is hacking postgres's source code to make the TODO: "allow
recompilation of views" (he send an email about that in another
thread)...

i think this is somewhat necesary to read:
http://wiki.postgresql.org/wiki/Developer_FAQ#Technical_Questions
and of course look at other files that acces that kind of info, for
example look at AlterTableNamespace() funtion in
src/backend/commands/tablecmds.c to find out for a complete example to
identify tables and views

--
Atentamente,
Jaime Casanova
Soporte y capacitación de PostgreSQL
Asesoría y desarrollo de sistemas
Guayaquil - Ecuador
Cel. +59387171157