Thread

Inheritance of functions

Andrzej Mazurkiewicz <andrzej.mazurkiewicz@polkomtel.com.pl> — 1999-11-04T15:10:54Z

Hello.
I have not got any help from SQL and GENERAL groups so I send my problem to
you.


In Postgres Users Guide, CREATE TABLE section, the following is stated:

 Postgres automatically allows the created table to inherit functions on
tables above it in the inheritance hierarchy. 

          Aside: Inheritance of functions is done according to the
conventions of the Common Lisp Object System (CLOS). 

I have tried different constructs but I have not been able to create such a
function. Can anybody send me an example of a function that will be
inherited by inherited table? I. e.
create table A (
.
.
);

create function F ...

create table B (
..
) inherits (A);

Now I assume that I can somehow use function F on table B 

The specific example is given below !!

Thank you, 
Regards,
Andrzej Mazurkiewicz


-----Original Message-----
From:	Andrzej Mazurkiewicz 
Sent:	27 paYdziernika 1999 18:09
To:	'pgsql-general@hub.org'
Subject:	RE: [GENERAL] FW: inheritance of functions

Hello.
Here is an example of my problem:

ccbslin2:~/lipa$ psql -c "drop database archimp0;" template1
DESTROYDB
ccbslin2:~/lipa$ psql -c "create database archimp0;" template1
CREATEDB
ccbslin2:~/lipa$ psql -f funinh1.sql archimp0
BEGIN WORK;
BEGIN
CREATE TABLE A (
        liczba float
);
CREATE
COMMIT WORK;
END

BEGIN WORK;
BEGIN
CREATE FUNCTION suma (A) RETURNS float
        AS 'SELECT $1.liczba AS suma;' LANGUAGE 'sql';
CREATE
COMMIT WORK;
END

BEGIN WORK;
BEGIN
CREATE TABLE B (
        liczwym float
) INHERITS (A)
;
CREATE
COMMIT WORK;
END

BEGIN WORK;
BEGIN
INSERT INTO A (liczba) VALUES (1.56);
INSERT 71414 1
COMMIT WORK;
END

BEGIN WORK;
BEGIN
INSERT INTO B (liczba, liczwym) VALUES (2.5, 3.2);
INSERT 71415 1
COMMIT WORK;
END

select liczba, suma(A) from A;
liczba|suma
------+----
  1.56|1.56
(1 row)

select liczba, suma(A) from A*;
liczba|suma
------+----
  1.56|1.56
   2.5| 2.5
(2 rows)

[Andrzej Mazurkiewicz]  --
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 
select liczba, suma(B) from B; [Andrzej Mazurkiewicz]         !!!!!!! 
ERROR:  Functions on sets are not yet supported [Andrzej Mazurkiewicz]
!!!!!!! 

[Andrzej Mazurkiewicz]  --
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 

EOF

----------------------------------------------------------------------------
--------------------------------------

After invoking psql:


archimp0=> select * from pg_proc where proname = 'suma';
proname|proowner|prolang|proisinh|proistrusted|proiscachable|pronargs|proret
set|prorettype|
proargtypes|probyte_pct|properbyte_cpu|propercall_cpu|proouti
n_ratio|prosrc                   |probin
-------+--------+-------+--------+------------+-------------+--------+------
---+----------+-------------------+-----------+--------------+--------------
+--------------+-------------------------+------
suma   |     302|     14|f       |t           |f            |       1|f
|       701|71393 0 0 0 0 0 0 0|        100|             0|             0|
100|SELECT $1.liczba AS suma;|-     
(1 row)

archimp0=> 

I am looking for working example !!!!!

Regards,
Andrzej Mazurkiewicz
	-----Original Message-----
	From:	Aaron J. Seigo [SMTP:aaron@gtv.ca]
	Sent:	27 paYdziernika 1999 17:39
	To:	Andrzej Mazurkiewicz; 'pgsql-general@hub.org'
	Subject:	Re: [GENERAL] FW: inheritance of functions

	hi...

	> >  Postgres automatically allows the created table to inherit
functions on
	> > tables above it in the inheritance hierarchy. 
	> > create table A (
	> > .
	> > .
	> > );
	> > 
	> > create function F ...
	> > 
	> > create table B (
	> > ..
	> > ) inherits (A);
	> > 
	> > Now I assume that I can somehow use function F on table B 

	you would be able to use function F on table B even if it didn't
inherit A. 

	however, if you construct rules, triggers, etc... on table A, these
should be
	inherited by table B.

	the manual is, as far as my experience has led me to believe,
referring to
	functions "bound" (for lack of a better word) to the parent
table....

	-- 
	Aaron J. Seigo
Sys Admin