Thread: [INTERFACES] my problems with ecpg and arrays

[INTERFACES] my problems with ecpg and arrays

From
"Coleman, Andrew"
Date:
Hi, I'm having problems loading (insert into ..) a c array into a postgres
table.
I have tried all the variations on syntax I can think of, and searched for
the
answer... and either didn't find it or didn't recognize it..

SHORT version:
How do I replace {1,2...} with a c array,
exec sql insert into testtab (fname,fid,farr) values
(:fname,:fid,'{1,2,3,4,5,6,7,8,9}');
?

LONG,LONG version:
typos are mine (I have to retype from the system I'm running postgres :( )
I can do this in psql:
create type int2array
(input=array_in,output=array_out,internallength=variable,element=int2);
create table sampletab2 (id int4, narr int2array);
insert into sampletab2 (id,narr) values (12,'{3,2}');
and everything looks ok with both \d sampletab2 and select * from sampletab2

And this code works great:
#include <stdio.h>
#include <libpq-fe.h>
#include <math.h>

exec sql whenever sqlerror sqlprint;
exec sql include sqlca;

exec sql begin declare section; int fid; int fidarr[10]; varchar[40]; varchar sqlcom[80];
exec sql end declare section;

main(){ int ii; printf("Begin \n"); fid=5; for (ii=0;ii<=9;ii++) {fidarr[ii]=ii;printf("fidarr[%d]=%d
\n",ii,fidarr[ii]);}; fname.len=sprintf(fname.arr,"doodah day"); printf("fid equals : %d \n",fid); exec sql connect to
testdb1;exec sql create table testtab (fname varchar(40),fid int, fidarr int[10]); exec sql insert into testtab
(fname,fid,farr)values
 
(:fname,:fid,'{1,2,3,4,5,6,7,8,9}'); exec sql commit; exec sql disconnect; printf ("Done \n");
}

How do a do something like:
exec sql insert into testtab (fname,fid,farr) values (:fname,:fid,:fidarr);

??
Thanks (and sorry for the long post)
andrew.


Re: [INTERFACES] my problems with ecpg and arrays

From
Michael Meskes
Date:
On Mon, Nov 08, 1999 at 10:39:12AM -0600, Coleman, Andrew wrote:
>   I'm having problems loading (insert into ..) a c array into a postgres
> table.
> I have tried all the variations on syntax I can think of, and searched for
> the
> answer... and either didn't find it or didn't recognize it..

This certainly looks like a bug. I will take care of it if I find the time
sometimes. Sorry, but I'm currently very busy.

Michael
-- 
Michael Meskes                         | Go SF 49ers!
Th.-Heuss-Str. 61, D-41812 Erkelenz    | Go Rhein Fire!
Tel.: (+49) 2431/72651                 | Use Debian GNU/Linux!
Email: Michael@Fam-Meskes.De           | Use PostgreSQL!


Re: [INTERFACES] my problems with ecpg and arrays

From
Michael Meskes
Date:
On Mon, Nov 08, 1999 at 10:39:12AM -0600, Coleman, Andrew wrote:
>   I'm having problems loading (insert into ..) a c array into a postgres
> table.
> I have tried all the variations on syntax I can think of, and searched for
> the
> answer... and either didn't find it or didn't recognize it..

I'm afraid you find a real problem here. I just didn't think about inserting
arrays. If you give ecpg an array of int it inserts every single value as
one int. That means:

insert into foo(bar) values(:intarray)

is equal to:

for (i=0;i<maxarray;i++)insert into foo(bar) values(:intarray[i])

How shall ecpg see that this time it is meant to insert the whole array?

Anyone with an idea?

Michael
-- 
Michael Meskes                         | Go SF 49ers!
Th.-Heuss-Str. 61, D-41812 Erkelenz    | Go Rhein Fire!
Tel.: (+49) 2431/72651                 | Use Debian GNU/Linux!
Email: Michael@Fam-Meskes.De           | Use PostgreSQL!


Re: [INTERFACES] my problems with ecpg and arrays

From
Michael Meskes
Date:
On Mon, Nov 08, 1999 at 10:39:12AM -0600, Coleman, Andrew wrote:
>   I'm having problems loading (insert into ..) a c array into a postgres
> table.
> I have tried all the variations on syntax I can think of, and searched for
> the
> answer... and either didn't find it or didn't recognize it..

I'm afraid you find a real problem here. I just didn't think about inserting
arrays. If you give ecpg an array of int it inserts every single value as
one int. That means:

insert into foo(bar) values(:intarray)

is equal to:

for (i=0;i<maxarray;i++)insert into foo(bar) values(:intarray[i])

How shall ecpg see that this time it is meant to insert the whole array?

Anyone with an idea?

Michael
-- 
Michael Meskes                         | Go SF 49ers!
Th.-Heuss-Str. 61, D-41812 Erkelenz    | Go Rhein Fire!
Tel.: (+49) 2431/72651                 | Use Debian GNU/Linux!
Email: Michael@Fam-Meskes.De           | Use PostgreSQL!


Re: [INTERFACES] my problems with ecpg and arrays

From
"Coleman, Andrew"
Date:
Thanks for looking into it. For the code I'm working on, it's no problem to
work around (messy, but
no problem).
>I'm afraid you find a real problem here. I just didn't think about
inserting
>arrays. If you give ecpg an array of int it inserts every single value as
>one int. That means:
>
>insert into foo(bar) values(:intarray)
>
>is equal to:
>
>for (i=0;i<maxarray;i++)
>    insert into foo(bar) values(:intarray[i])
>How shall ecpg see that this time it is meant to insert the whole array?
>
>Anyone with an idea?

I'm guessing you're mostly directing that at people who are atleast vaguely
familiar with the
way pg and ecpg works internally ;)

>
>Michael

Thanks again (both for looking into it and for ecpg itself),
andrew.



Re: [INTERFACES] my problems with ecpg and arrays

From
Michael Meskes
Date:
On Mon, Nov 15, 1999 at 08:27:36AM -0600, Coleman, Andrew wrote:
> Thanks for looking into it. For the code I'm working on, it's no problem to
> work around (messy, but
> no problem).

Hopefully I find a better solution. :-)

> I'm guessing you're mostly directing that at people who are atleast vaguely
> familiar with the
> way pg and ecpg works internally ;)

Yes. :-)

> Thanks again (both for looking into it and for ecpg itself),

I'm glad it is actually used.

Michael
-- 
Michael Meskes                         | Go SF 49ers!
Th.-Heuss-Str. 61, D-41812 Erkelenz    | Go Rhein Fire!
Tel.: (+49) 2431/72651                 | Use Debian GNU/Linux!
Email: Michael@Fam-Meskes.De           | Use PostgreSQL!