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* libpq++ and arrays?
@ 1999-05-14 21:07 Alf Lewerken <lewerken@mail.bicos.de>
1999-05-15 11:38 ` Re: [INTERFACES] libpq++ and arrays? Patrick Welche <prlw1@newn.cam.ac.uk>
0 siblings, 1 reply; 3+ messages in thread
From: Alf Lewerken @ 1999-05-14 21:07 UTC (permalink / raw)
To: pgsql-interfaces
Hi all
I have the following problem:
I'm using libpq++ to acces a Postgres-Database.
The table was created in psql using:
create table test values (nr int4, some_value float4[]);
in my C++-program a piece of code is:
main()
{
char *nr_string, *some_other_string;
PgDatabase test(pgenv, "test");
test.Exec("begin");
test.Exec("declare c cursor for select * from test");
for(int i=0; i<test.Tuples();i++)
{
nr_string = test.GetValue(i, "nr"); // obtaining the value in 'nr' is easy
some_other_string = test.GetValue(i, "some_value[1]"); // this gives an error
// PQgetvalue: ERROR! field number -1 is out of range
// so how do I obtain values in some_value[1], some_value[2] .... ?
}
}
any help would be appreciated.
bye
Alf Lewerken
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: [INTERFACES] libpq++ and arrays?
1999-05-14 21:07 libpq++ and arrays? Alf Lewerken <lewerken@mail.bicos.de>
@ 1999-05-15 11:38 ` Patrick Welche <prlw1@newn.cam.ac.uk>
0 siblings, 0 replies; 3+ messages in thread
From: Patrick Welche @ 1999-05-15 11:38 UTC (permalink / raw)
To: lewerken@mail.bicos.de; +Cc: pgsql-interfaces
Alf Lewerken wrote:
>
> I have the following problem:
> I'm using libpq++ to acces a Postgres-Database.
>
> The table was created in psql using:
> create table test values (nr int4, some_value float4[]);
...
> // so how do I obtain values in some_value[1], some_value[2] .... ?
How about
create table test (nr int4, some_value float4[]);
insert into test values (1,'{1,2,3}');
insert into test values (2,'{2,4,6}');
insert into test values (3,'{3,6,9}');
#include <iostream>
#include <libpq++.h>
int main()
{
const char *nr_string, *val1, *val2;
PgDatabase test("test");
test.Exec("select nr,test.some_value[1] as val1, test.some_value[2] as val2 "
"from test");
for(int i=0; i<test.Tuples();i++)
{
nr_string = test.GetValue(i, "nr");
val1 = test.GetValue(i, "val1");
val2 = test.GetValue(i, "val2");
cout<<"nr_string: "<<nr_string
<<"\nsome_value[1]: "<<val1
<<"\nsome_value[2]: "<<val2<<'\n';
}
return 0;
}
% a.out
nr_string: 1
some_value[1]: 1
some_value[2]: 2
nr_string: 2
some_value[1]: 2
some_value[2]: 4
nr_string: 3
some_value[1]: 3
some_value[2]: 6
Add cursors to taste :)
Cheers,
Patrick
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: [INTERFACES] libpq++ and arrays?
@ 1999-05-16 08:19 Alf Lewerken <lewerken@mail.bicos.de>
0 siblings, 0 replies; 3+ messages in thread
From: Alf Lewerken @ 1999-05-16 08:19 UTC (permalink / raw)
To: prlw1@cam.ac.uk; +Cc: pgsql-interfaces
>
>How about
>
>
>Add cursors to taste :)
>
>Cheers,
>
>Patrick
>
Thank you!
That saved my day :-)
bye
Alf Lewerken
^ permalink raw reply [nested|flat] 3+ messages in thread
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1999-05-14 21:07 libpq++ and arrays? Alf Lewerken <lewerken@mail.bicos.de>
1999-05-15 11:38 ` Patrick Welche <prlw1@newn.cam.ac.uk>
1999-05-16 08:19 Re: [INTERFACES] libpq++ and arrays? Alf Lewerken <lewerken@mail.bicos.de>
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