Hi, Oliver,
On Thu, 28 Oct 2004 15:18:13 +1300
Oliver Jowett <oliver@opencloud.com> wrote:
> - Implementations of PGobject should provide a ctor taking a single
> String; this is called by the driver to construct non-null objects.
Is it possible to use a static factory function instead?
This would make it possible to produce different subclasses depending on
the String, which would be useful e. G. for PostGIS, als all the
geometry classes share the same postgres type "geometry".
> When we come to do binary-format types, I'd expect we would have a
> subinterface (PGbinaryobject?) that adds whatever methods are needed for
> binary parameter formatting. Objects that implement PGbinaryobject
> become candidates for binary transfer.
What do you think about the factory / handler object approach that AFAIR
was discussed here some days ago?
So the driver gets registered one PGfactory for every postgres type, and
this factory then has methods to transform objects to text and binary
representation and vice-versa.
This would allow us to read and write instances of third-party defined
classes that don't implement any postgres specific interface.
We still could have a default factory implementation that gets used
whenever any legacy application uses PGObject subclasses.
Markus
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