Re: variables in procedures

How can I distinguish between the name and the value of a variable?

Example:

CREATE FUNCTION test(VARCHAR) RETURNS INTEGER AS '

DECLARE
col1 ALIAS FOR $1
BEGIN
select col1 from tab where col1=´´col1´´;
END;
´ LANGUAGE 'plpgsql';

Is my doubt understood?

--
Porqué usar una base de datos relacional cualquiera,
si podés usar PostgreSQL?
-----------------------------------------------------------------
Martín Marqués | mmarques(at)unl(dot)edu(dot)ar
Programador, Administrador, DBA | Centro de Telematica
Universidad Nacional
del Litoral
-----------------------------------------------------------------

Martin,

> How can I distinguish between the name and the value of a variable?

You need to name your variables something *different* from your column
names. Otherwise, you will get unexpected errors.

A practice I usually follow is prefixing my column-substitiution
variables with "v_". This allows me, and the PL/pgSQL parser, to keep
the variables straight from the columns. I also need to fix your
procedure in a couple of places. Thus:

CREATE FUNCTION test(VARCHAR) RETURNS INTEGER AS '

DECLARE
v_col1 ALIAS FOR $1;
v_result INT;
BEGIN
select col1 INTO v_result
from tab where col1 = v_col1;
RETURN v_result;
END;
´ LANGUAGE 'plpgsql';

Other SQL-procedural languages (e.g. Transact-SQL) force you to prefix
your variables with special characters. In PL/pgSQL, it's up to you to
maintain consistency.

-Josh Berkus

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Josh Berkus
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On Fri, 30 Nov 2001, [iso-8859-1] Martn Marqus wrote:

> How can I distinguish between the name and the value of a variable?
>
> Example:
>
> CREATE FUNCTION test(VARCHAR) RETURNS INTEGER AS '
>
> DECLARE
> col1 ALIAS FOR $1
> BEGIN
> select col1 from tab where col1=col1;
> END;
> LANGUAGE 'plpgsql';
>
>
> Is my doubt understood?

AFAIK you don't distinguish, you'll probably need to name
the variable something else.