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Date: Wed, 15 Aug 2012 20:31:07 -0400
From: Bruce Momjian <bruce@momjian.us>
To: Pavel Stehule <pavel.stehule@gmail.com>
Cc: Josh Kupershmidt <schmiddy@gmail.com>,
	pgsql-docs <pgsql-docs@postgresql.org>
Subject: Re: [BUGS] documentation bug - behave of NEW a OLD in plpgsql's
	triggers
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On Wed, Sep  7, 2011 at 03:40:19PM +0200, Pavel Stehule wrote:
> 2011/9/7 Josh Kupershmidt <schmiddy@gmail.com>:
> > On Tue, Sep 6, 2011 at 10:54 PM, Bruce Momjian <bruce@momjian.us> wrote:
> >> Josh Kupershmidt wrote:
> >>> How about a doc tweak like the attached?
> >>
> >> Perfect.  Applied to 9.0, 9.1, and head.  Thanks.  Sorry for the delay.
> >
> > Err, as Tom's first comment in this thread explains, Pavel and I were
> > both wrong: the variables in question are indeed NULL, not undefined.
> > I think the docs were fine the way they were.
> 
> There is maybe bug - these variables are defined, but they has not
> assigned tupledesc, so there is not possible do any test
> 
> postgres=# create table omega (a int, b int);
> CREATE TABLE
> postgres=# create or replace function foo_trig()
> postgres-# returns trigger as $$
> postgres$# begin
> postgres$#   raise notice '%', new;
> postgres$#   return null;
> postgres$# end;
> postgres$# $$ language plpgsql;
> CREATE FUNCTION
> postgres=# create trigger xxx after delete on omega for each row
> execute procedure foo_trig();
> CREATE TRIGGER
> postgres=# insert into omega values(20);
> INSERT 0 1
> postgres=# delete from omega;
> ERROR:  record "new" is not assigned yet
> DETAIL:  The tuple structure of a not-yet-assigned record is indeterminate.
> CONTEXT:  PL/pgSQL function "foo_trig" line 3 at RAISE
> 
> so current text in documentation is not correct too.

I used your queries to test NEW/OLD on DELETE/INSERT, respectively, and
for statement-level triggers, and you are right that they are
unassigned, not NULL.

The attached patch fixes our documentation for PG 9.3.

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +

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diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml
new file mode 100644
index ab40845..07fba57
*** a/doc/src/sgml/plpgsql.sgml
--- b/doc/src/sgml/plpgsql.sgml
*************** RAISE unique_violation USING MESSAGE = '
*** 3403,3409 ****
        <para>
         Data type <type>RECORD</type>; variable holding the new
         database row for <command>INSERT</>/<command>UPDATE</> operations in row-level
!        triggers. This variable is <symbol>NULL</symbol> in statement-level triggers
         and for <command>DELETE</command> operations.
        </para>
       </listitem>
--- 3403,3409 ----
        <para>
         Data type <type>RECORD</type>; variable holding the new
         database row for <command>INSERT</>/<command>UPDATE</> operations in row-level
!        triggers. This variable is unassigned in statement-level triggers
         and for <command>DELETE</command> operations.
        </para>
       </listitem>
*************** RAISE unique_violation USING MESSAGE = '
*** 3415,3421 ****
        <para>
         Data type <type>RECORD</type>; variable holding the old
         database row for <command>UPDATE</>/<command>DELETE</> operations in row-level
!        triggers. This variable is <symbol>NULL</symbol> in statement-level triggers
         and for <command>INSERT</command> operations.
        </para>
       </listitem>
--- 3415,3421 ----
        <para>
         Data type <type>RECORD</type>; variable holding the old
         database row for <command>UPDATE</>/<command>DELETE</> operations in row-level
!        triggers. This variable is unassigned in statement-level triggers
         and for <command>INSERT</command> operations.
        </para>
       </listitem>

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