Thread: Problem with API (libpq) - detailed error codes

Hi!

I started programming PostgreSQL database with libpq API (client
side). It looks very easy, but unexpected I found problem, which I
cannot solve myself.
If function PQexec fails, I can get error code using PQresultStatus.
But returned codes are very generally and do not specify what really
happen. I can get detailed error description using PQerrorMessage
function, but I need detailed error code (number).

For instance, if I create table, I would like to know, that operation
failed because:
- table already exist
- sql syntax error
- invalid columnt type
and so on.

I searched documents about libpq API and even header file
'internal/libpq-int.h' but I didn't found any interesting.

I would be very gracefully for any hint.

Best regards,
Adam Bukla

Adam.Bukla@interia.pl (Adam Bukla) writes:
> If function PQexec fails, I can get error code using PQresultStatus.
> But returned codes are very generally and do not specify what really
> happen. I can get detailed error description using PQerrorMessage
> function, but I need detailed error code (number).

Beginning in Postgres 7.4, there are standard SQLSTATE error codes
available (see PQresultErrorField), but older releases do not have them.

            regards, tom lane

Hi!

Thanks ljb and Tom Lane - it's exactly what I wanted.
I read documentation to 7.3 so I couldn't find PQresultErrorField function.
I'm suprised, that such necessary functionality exist only in 7.4 version.

Thanks once again,
 Adam Bukla