Re: Problem in GNATColl when using prepared queries: GNATCOLL.SQL.POSTGRES.GNADE.POSTGRESQL_ERROR is raised

[Emmanuel Briot <briot.emmanuel@gmail.com>]

> I've done some further digging, and it appears that GNATColl thinks the
> result is binary data when the query is prepared. When the same query is
> executed without preparing it, the data is returned just fine as Integer
> and String respectively.

Your analysis is correct.
The fix here is actually trivial.

in gnatcoll-sql-postgres-gnade.adb, replace the code for

 function PQexecPrepared
           (Conn : System.Address;
            Name : String;
            Nparams : Natural := 0;
            Values  : CS.chars_ptr_array;
            Lengths : System.Address := System.Null_Address;
            Formats : System.Address := System.Null_Address;
            Format  : Natural := 0) return System.Address;

so that "Format" defaults to 1 instead of 0.

That forces postgreSQL to return values as text instead of binary. The
latter format is not supported by GNATCOLL (nor was it supported by
GNADE). There is too much machine-dependent handling here.