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* a couple of newbie question
@ 2000-04-16 18:57 Matthew Denny <mdenny@CS.Berkeley.EDU>
2000-04-16 19:17 ` Re: [NOVICE] a couple of newbie question D. Duccini <duccini@backpack.com>
0 siblings, 1 reply; 3+ messages in thread
From: Matthew Denny @ 2000-04-16 18:57 UTC (permalink / raw)
To: pgsql-interfaces; pgsql-novice@postgresql.org
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? Similarly, how do
I tell that a value put into a variable by a fetch call is NULL or
not?
On a different note, is there any list of error codes for the actual
postgreSQL errors, or is the only thing a user can get back is the
text message in sqlca.sqlerrm.sqlerrmc (e.g. no associated error #)?
Any help would be greatly appreciated.
thanks,
Matt
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: [NOVICE] a couple of newbie question
2000-04-16 18:57 a couple of newbie question Matthew Denny <mdenny@CS.Berkeley.EDU>
@ 2000-04-16 19:17 ` D. Duccini <duccini@backpack.com>
0 siblings, 0 replies; 3+ messages in thread
From: D. Duccini @ 2000-04-16 19:17 UTC (permalink / raw)
To: Matthew Denny <mdenny@CS.Berkeley.EDU>; +Cc: pgsql-interfaces; pgsql-novice@postgresql.org
You insert it by NOT inserting it.
insert into test_table (col_x, col_y) values (:x, :y);
you basically omit any column you do not want to insert values for
-duck
On Sun, 16 Apr 2000, 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? Similarly, how do
> I tell that a value put into a variable by a fetch call is NULL or
> not?
>
> On a different note, is there any list of error codes for the actual
> postgreSQL errors, or is the only thing a user can get back is the
> text message in sqlca.sqlerrm.sqlerrmc (e.g. no associated error #)?
>
> Any help would be greatly appreciated.
>
> thanks,
> Matt
>
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^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: a couple of newbie question
@ 2000-04-16 21:03 Ivo Simicevic <ivo@ultra.hr>
0 siblings, 0 replies; 3+ messages in thread
From: Ivo Simicevic @ 2000-04-16 21:03 UTC (permalink / raw)
To: pgsql-interfaces
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.
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2000-04-16 18:57 a couple of newbie question Matthew Denny <mdenny@CS.Berkeley.EDU>
2000-04-16 19:17 ` D. Duccini <duccini@backpack.com>
2000-04-16 21:03 Re: a couple of newbie question Ivo Simicevic <ivo@ultra.hr>
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