Re: JDBC not returning update count from updateable view

But this works just fine when using libpq via c++.

From: davecramer(at)gmail(dot)com [mailto:davecramer(at)gmail(dot)com] On Behalf Of Dave Cramer
Sent: 26 February 2013 12:23
To: Russell Keane
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: [GENERAL] JDBC not returning update count from updateable view

As far as I remember this is an artifact of using rules to update a table.

Dave Cramer

dave.cramer(at)credativ(dot)ca
http://www.credativ.ca

On Mon, Feb 25, 2013 at 2:52 PM, Russell Keane <Russell(dot)Keane(at)inps(dot)co(dot)uk<mailto:Russell(dot)Keane(at)inps(dot)co(dot)uk>> wrote:
Hi,

We have a table which is inserted to and update via a view (using rules / functions).

We are trying to update this from JDBC but the view update command (on the java side) doesn't return the count of rows updated. I assume this is because the postgres update function actually returns a tuple rather than a single count.

Any ideas?

A simplified version of the java bit:

JdbcTemplate is: org.springframework.jdbc.core.JdbcTemplate;

public final int updateTest(final String updateSQL, final Object[] args) {
JdbcTemplate template = createJdbcTemplate();
return template.update(updateSQL, args);
}

And the postgres object creation (again simplified):

--PG START

drop table if exists msg_table cascade;
drop sequence if exists msg_seq;
drop sequence if exists msg_aud_seq;
create sequence msg_seq;
create sequence msg_aud_seq;

CREATE TABLE msg_table
(
aud_seq int default nextval('msg_aud_seq'),
status int default 1,
id int default nextval('msg_seq'),
val int
);

create or replace view msg as
select
aud_seq,
id,
status,
val
from msg_table;

-- audit the original record
CREATE OR REPLACE FUNCTION audit_original_record(msg) RETURNS void AS $$
BEGIN
UPDATE msg_table
SET
status = 2
WHERE
aud_seq = $1.aud_seq;
END;
$$ LANGUAGE plpgsql;

-- insert function
CREATE OR REPLACE FUNCTION process_insert(msg) RETURNS integer AS $body$
declare new_id integer;

BEGIN

INSERT INTO msg_table
(
val
)
SELECT
$1.val

RETURNING id INTO new_id;

return new_id;
END;
$body$ LANGUAGE plpgsql;

-- update function
CREATE OR REPLACE FUNCTION process_update(msg, msg) RETURNS void AS $body$
BEGIN
INSERT INTO msg_table
(
id,
val
)
SELECT
$1.id<http://1.id>,
$1.val;

EXECUTE audit_original_record($2);

END;
$body$ LANGUAGE plpgsql;

-- insert to msg
create or replace rule msg__rule_ins as on insert to msg
do instead
SELECT process_insert(NEW);

-- update to msg
create or replace rule msg__rule_upd as on update to msg
do instead
SELECT
COUNT(process_update(NEW, OLD))
WHERE
NEW.status = 1;

alter sequence msg_seq restart 1;
alter sequence msg_aud_seq restart 1;

delete from msg_table;

insert into msg
(val)
values
(1),
(2),
(66);

select * from msg;

update msg
set val = 5
where id = 1;

select * from msg;

--PG END

Thanks for any help you can give me.

Regards,

Russell Keane
INPS
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