Re: PL/pgSQL: SELECT INTO EXACT - Mailing list pgsql-patches

From Bruce Momjian
Subject Re: PL/pgSQL: SELECT INTO EXACT
Date
Msg-id 200507300424.j6U4OPW22653@candle.pha.pa.us
Whole thread Raw
In response to PL/pgSQL: SELECT INTO EXACT  (Matt Miller <mattm@epx.com>)
List pgsql-patches
Sorry, patch removed from the queue.  I now see the later discussion.

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

Matt Miller wrote:
> This patch implements an optional EXACT keyword after the INTO keyword
> of the PL/pgSQL SELECT INTO command.  The motivation is to come closer
> to Oracle's SELECT INTO behavior: when SELECTing INTO scalar targets,
> raise an exception and leave the targets untouched if the query does not
> return exactly one row.  This patch does not go so far as to raise an
> exception, but it can simplify porting efforts from PL/SQL.  I also feel
> that this EXACT behavior is overall a bit cleaner than the current
> PL/pgSQL behavior.  Maybe I've just been brainwashed by years of
> Oracle'ing.
>
> Here are three excerpts from the patched PL/pgSQL documentation:
>
> "If the EXACT option is specified, then target will not be set unless
> the query returns exactly one row"
>
> "You can check the special FOUND variable after a SELECT INTO to
> determine whether the statement was successful. ... an EXACT query is
> successful only if exactly 1 row is returned."
>
> "...GET DIAGNOSTICS (see Section 35.6.6) to retrieve ROW_COUNT. After a
> SELECT INTO EXACT statement ROW_COUNT ... will be equal to 0, 1, or 2,
> indicating no matching rows, exactly one matching row, or greater than
> one matching row, respectively."

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