From: Ivo Simicevic <ivo@ultra.hr>
To: pgsql-interfaces@postgreSQL.org
Subject: Re: a couple of newbie question
Date: Sun, 16 Apr 2000 23:03:12 +0200
Message-ID: <20000416230312.A1117@ultra.hr> (raw)
On Sun, Apr 16, 2000 at 11:57:38AM -0700, Matthew Denny wrote:
>
> I know this question is probably fairly elementary, but I could not
> find the answer in the docs or mailing list archives. How does one handle
> NULL values in the embedded SQL interface? For example, if I have a
> statement:
>
> exec sql insert into test_table values(:foo, :x, :y)
>
> and foo represents a CHAR attribute (represented by a string in C) that I
> want to set to NULL, how do I go about doing this?
There are two ways :
exec sql insert into test_table values (NULL,:x,:y) or more properly
define indicator variable in DECLARE section and use it to insert null value
e.g.
EXEC SQL BEGIN DECLARE SECTION;
char foo[10];
int x;
int y;
int indicator;
EXEC SQL END DECLARE SECTION;
.....
indicator=-1;
EXEC SQL INSERT INTO test_table VALUES (:foo:indicator,:x,:y);
> Similarly, how do
> I tell that a value put into a variable by a fetch call is NULL or
> not?
>
You can do it the same way:
EXEC SQL SELECT foo,x,y
INTO :foo:indicator,:x,:y
......
and then check for indicator value.
GL
Ivo.
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-interfaces@postgresql.org
Cc: ivo@ultra.hr
Subject: Re: a couple of newbie question
In-Reply-To: <20000416230312.A1117@ultra.hr>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox