On Thu, Jan 15, 2004 at 08:29:41PM +0900, Michael Glaesemann wrote:
> >Is there a problem with the built in definitions of point and interval?
>
> I'm thinking along the lines of the temporal proposals Date, Darwen,
> and Lorentzos ("Temporal Data and the Relational Model"). Their
> "interval" type is more along the lines of a beginning and end time,
> such as ['2003-1-23':'2003-1-25'], rather than just '2 days'.
Maybe it's tangential to this discussion, but there's a type to store
that kind of intervals. It's called tinterval. ISTM it's not too much
documented, and I haven't really used it.
alvherre=> select tinterval('2003-10-28', '2004-11-05');
tinterval
-----------------------------------------------------
["2003-10-28 00:00:00-03" "2004-11-05 00:00:00-03"]
(1 fila)
alvherre=> select tinterval('2003-10-28', '2004-11-05') && tinterval('2003-10-05', '2003-10-15');
?column?
----------
f
(1 fila)
alvherre=> select tinterval('2003-10-28', '2004-11-05') && tinterval('2003-10-05', '2003-11-15');
?column?
----------
t
(1 fila)
(There are other operators, of course ...)
--
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
Criptografía: Poderosa técnica algorítmica de codificación que es
empleada en la creación de manuales de computadores.
