Обсуждение: Date/Time atributes and binary cursors

Hi there.

I'm trying to read a timestamp without timezone attribute, using binary cursors. I can read the data but i don't know
whatto do with it. I would like to convert it to a time_t or tm struct. How can i do this? 

I'm using postgresql 7.4 on Debian sid.

Here's a snippet of the code i'm using:

...
#include <postgresql/pgtypes_timestamp.h>
...
timestamp *ts; ts = (timestamp *) PQgetvalue(res, i, f_num);


I would like to use date attributes too.

Thanks in advance.

--
Gonçalo Marrafa <gjm@uevora.pt>

Gonçalo Marrafa wrote:
> I'm trying to read a timestamp without timezone attribute, using binary
> cursors. I can read the data but i don't know what to do with it. I would
> like to convert it to a time_t or tm struct. How can i do this?
> 
> I'm using postgresql 7.4 on Debian sid.
> 
> Here's a snippet of the code i'm using:
> 
> ...
> #include <postgresql/pgtypes_timestamp.h>
> ...
> timestamp *ts; ts =3D (timestamp *) PQgetvalue(res, i, f_num);
> 
> 
> I would like to use date attributes too.

Disclaimer: relying on binary cursor data format is probably a bad idea.

A date is returned as a 4-byte big-endian integer representing the number
of days since POSTGRES_EPOCH_DATE.
A timestamp is returned as an 8-byte big-endian double precision number of
seconds since POSTGRES_EPOCH_DATE.
A time is returned as an 8-byte big-endian double precision number of
seconds since midnight.
POSTGRES_EPOCH_DATE is January 1, 2000 (2000-01-01).

Note that binary cursor results are in network data order (big-endian)
starting with PostgreSQL-7.4 (versus native server order pre-7.4). This
means they need to be byte-swapped if your client runs on an Intel-type
little-endian system.

Thanks.

Do Postgres/libpq have functions for converting between Unix/Postgres date/time representations or do i have to do it
byhand? 

Thanks again.

> A date is returned as a 4-byte big-endian integer representing the number
> of days since POSTGRES_EPOCH_DATE.
> A timestamp is returned as an 8-byte big-endian double precision number of
> seconds since POSTGRES_EPOCH_DATE.
> A time is returned as an 8-byte big-endian double precision number of
> seconds since midnight.
> POSTGRES_EPOCH_DATE is January 1, 2000 (2000-01-01).
>
> Note that binary cursor results are in network data order (big-endian)
> starting with PostgreSQL-7.4 (versus native server order pre-7.4). This
> means they need to be byte-swapped if your client runs on an Intel-type
> little-endian system.
>


--
Gonçalo Marrafa <gjm@uevora.pt>

select extract(epoch from timestamp 'oct 1 2004 10:11:17');

On Tue, Apr 06, 2004 at 10:04:03AM +0100, Gonçalo Marrafa wrote:
> Thanks.
> 
> Do Postgres/libpq have functions for converting between Unix/Postgres date/time representations or do i have to do it
byhand?
 
> 
> Thanks again.
> 
>  
> > A date is returned as a 4-byte big-endian integer representing the number
> > of days since POSTGRES_EPOCH_DATE.
> > A timestamp is returned as an 8-byte big-endian double precision number of
> > seconds since POSTGRES_EPOCH_DATE.
> > A time is returned as an 8-byte big-endian double precision number of
> > seconds since midnight.
> > POSTGRES_EPOCH_DATE is January 1, 2000 (2000-01-01).
> > 
> > Note that binary cursor results are in network data order (big-endian)
> > starting with PostgreSQL-7.4 (versus native server order pre-7.4). This
> > means they need to be byte-swapped if your client runs on an Intel-type
> > little-endian system.
> > 
> 
> 
> -- 
> Gonçalo Marrafa <gjm@uevora.pt>



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