On Tue, May 19, 2009 at 8:17 AM, Sebastien FLAESCH <sf@xxxxxxx> wrote:
> Yes, good point.
>
> I realize now that I would have expected libpq to give me a way to specify
> the exact decoration or precision of INTERVAL parameters...
>
> As you can do with ODBC's SQLBindParameter(), where you specify the C type,
> SQL type, precision/scale or length ...
> I believe this is important when it comes to data type conversion (for ex,
> when you want to insert a numeric/date/time into a char or the other way).
> => sort of cast, actually...
>
> I known libpq functions like PQexecParams() or PQexecPrepared() have a
> paramFormats[] parameter to specify if the buffer will hold a string
> or the binary representation of the value... but that would not help
> much (I don't want to deal with internal structures!).
You might want to take a look at 'libpqtypes'. It exposes the
internal formats binary formats in easy to use structures.
e.g. (in libpqtypes.h)
typedef struct
{
int years;
int mons;
int days;
int hours;
int mins;
int secs;
int usecs;
} PGinterval;
I was curious, and decided to see what happens when you inserted an
interval with the following code snippet:
PGinterval i;
memset(&i, 0, sizeof(i));
i.secs = 1000000;
PQputf(p, "%interval", &i);
PQparamExec(c, p, "insert into foo values ($1)", 0);
select * from foo;
i
-----------
277:46:40
also, libpqtypes always sends in binary which is much faster for the
date/time types.
http://libpqtypes.esilo.com/
merlin
--
Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general
