Thread: libpq++ and arrays?

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

I've been upgrading postgresql 6.4.2 to 6.5. It seems like the jdbc driver
included with postgres 65 doesn't work correctly:
java.lang.IllegalArgumentException: Argument # > Arg length

or am i doing something wrong ?

-Yves

On Fri, 14 May 1999, Alf Lewerken wrote:

> 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
> 

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Then they laugh at you.
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