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* refer a column as a varible name?
@ 2005-09-12 15:21 gherzig@fmed.uba.ar
0 siblings, 1 reply; 3+ messages in thread
From: gherzig@fmed.uba.ar @ 2005-09-12 15:21 UTC (permalink / raw)
To: pgsql-sql
Hi all. I have troubles trying to achieve this assignment:
suppose the
type mycolumn as (field1, varchar, field2 varchar)
and
field_name = ''field1''
and returnValue declared as mycolumn
...
can i say returnValue.$field_name = ''ok''?
There is a way to achieve this piece of code?
Thanks a lot!
--
Gerardo Herzig
Direccion General de Organizacion y Sistemas
Facultad de Medicina
U.B.A.
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: refer a column as a varible name?
@ 2005-09-12 23:03 Michael Fuhr <mike@fuhr.org>
parent: gherzig@fmed.uba.ar
0 siblings, 1 reply; 3+ messages in thread
From: Michael Fuhr @ 2005-09-12 23:03 UTC (permalink / raw)
To: gherzig@fmed.uba.ar; +Cc: pgsql-sql
On Mon, Sep 12, 2005 at 12:21:22PM -0300, gherzig@fmed.uba.ar wrote:
> suppose the
>
> type mycolumn as (field1, varchar, field2 varchar)
> and
>
> field_name = ''field1''
>
> and returnValue declared as mycolumn
> ...
> can i say returnValue.$field_name = ''ok''?
To achieve this in PL/pgSQL you'll need to use a conditional statement
(IF field_name = 'field1' THEN ...). I'm not sure if a solution
involving EXECUTE is possible; if so then it's probably non-obvious.
What version of PostgreSQL are you using, and do you have a requirement
to use PL/pgSQL? In 8.0 PL/Perl can return composite types and such
an assignment would be trivial:
CREATE TYPE mycolumn AS (field1 varchar, field2 varchar);
CREATE FUNCTION foo(varchar) RETURNS mycolumn AS $$
my $field_name = $_[0];
my $returnValue = {$field_name => "ok"};
return $returnValue;
$$ LANGUAGE plperl IMMUTABLE STRICT;
SELECT * FROM foo('field1');
field1 | field2
--------+--------
ok |
(1 row)
SELECT * FROM foo('field2');
field1 | field2
--------+--------
| ok
(1 row)
--
Michael Fuhr
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: refer a column as a varible name?
@ 2005-09-13 18:09 gherzig@fmed.uba.ar
parent: Michael Fuhr <mike@fuhr.org>
0 siblings, 0 replies; 3+ messages in thread
From: gherzig@fmed.uba.ar @ 2005-09-13 18:09 UTC (permalink / raw)
To: Michael Fuhr <mike@fuhr.org>; +Cc: gherzig@fmed.uba.ar; pgsql-sql
Im using pg 8.0. I personally dont have problem in using pl/perl, but none
of my companions is a perl programmer, so i guess the IF..THEN seems to be
an easy (altough not preferable) solution.
Thank you very much Michael.
Gerardo
> On Mon, Sep 12, 2005 at 12:21:22PM -0300, gherzig@fmed.uba.ar wrote:
>> suppose the
>>
>> type mycolumn as (field1, varchar, field2 varchar)
>> and
>>
>> field_name = ''field1''
>>
>> and returnValue declared as mycolumn
>> ...
>> can i say returnValue.$field_name = ''ok''?
>
> To achieve this in PL/pgSQL you'll need to use a conditional statement
> (IF field_name = 'field1' THEN ...). I'm not sure if a solution
> involving EXECUTE is possible; if so then it's probably non-obvious.
>
> What version of PostgreSQL are you using, and do you have a requirement
> to use PL/pgSQL? In 8.0 PL/Perl can return composite types and such
> an assignment would be trivial:
>
> CREATE TYPE mycolumn AS (field1 varchar, field2 varchar);
>
> CREATE FUNCTION foo(varchar) RETURNS mycolumn AS $$
> my $field_name = $_[0];
> my $returnValue = {$field_name => "ok"};
> return $returnValue;
> $$ LANGUAGE plperl IMMUTABLE STRICT;
>
> SELECT * FROM foo('field1');
> field1 | field2
> --------+--------
> ok |
> (1 row)
>
> SELECT * FROM foo('field2');
> field1 | field2
> --------+--------
> | ok
> (1 row)
>
> --
> Michael Fuhr
>
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>
--
Gerardo Herzig
Direccion General de Organizacion y Sistemas
Facultad de Medicina
U.B.A.
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2005-09-12 15:21 refer a column as a varible name? gherzig@fmed.uba.ar
2005-09-12 23:03 ` Michael Fuhr <mike@fuhr.org>
2005-09-13 18:09 ` gherzig@fmed.uba.ar
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