On Sat, 19 Sep 1998, David Warnock wrote:
> Peter T Mount wrote:
>
> > > But are there any Open Source tools to do this? I am interested in
> > > contributing to such a project as I need it for several open source
> > > projects I have planned.
> >
> > I added this functionality into the PostgreSQL JDBC driver recently for
> > the next release (6.4 due out Oct 1st, currently in beta).
> >
> > It works if a java object is Serializable, and it's full class name
> > matches the name of a table.
> >
> > ie: mypackage.myclass would map to the table mypackage_myclass.
> >
> > Then when the ResultSet.getObject() or PreparedStatement.setObject()
> > methods are called, the driver uses the Reflection API to do the transfer.
> >
> > It works quite well. The only limitations are that the class/table names
> > are limited to 31 characters, and the 8k tuple limit (although this should
> > be extensible in 6.4 at database creation time).
>
> Peter,
>
> This is very interesting however, it is not really what I am looking
> for. Postgresql is one the of the dbms we are using via the JDBC driver
> - and mnay thanks for that.
>
> However, I am looking for something a lot more powerful at modelling
> business objects and mapping them onto tables. The mappings are not
> simple one object - one table and they also need to support validation,
> business rules etc.
The new rules system may help there. Also, the new object code does handle
multiple tables if the serialized class contains other serialized classes,
or the super class is serializable.
> I may decide to buld something and make it available - it would then be
> able to make use of JINI and JavaSpaces and thus allow distributed
> business objects.
>
> Thanks for your answer and for the work on Postgresql. While I have
> youn attention can I ask some quick questions about Postgresql.
>
> 1. Is there any work being done by anyone on a windows port (for my
> customers - I am moving to pure linux client and server)?
I presume you mean the Server? I did hear on the list yesterday of someone
who's having some success on porting PostgreSQL to Win NT. Probably not
for 6.4, but 6.5 will almost certanly support it.
> 2. Will 6.4 support Unicode fully when using JDBC?
No, not fully. I am targeting that now for 6.5
> 3. What options and possibilities are there for simple triggers (eg to
> stop parents being deleted when there are children, keep an invoice
> total up-to-date etc)?
Triggers have to be written in C and use the SPI interface. I haven't
looked at the new rules system, but at first glance, it's done in SQL, so
it's possible.
--
Peter T Mount [EMAIL PROTECTED]
Main Homepage: http://www.retep.org.uk
PostgreSQL JDBC Faq: http://www.retep.org.uk/postgres
Java PDF Generator: http://www.retep.org.uk/pdf
