Re: design question

gym dot scuba dot kennedy at gmail wrote:

> Tell me, do you just use
> one data type in Java, Strings? Of course not. So why would you do
> the same in the db? Do you only have 1 class in Java, class generic?
> Of course not. So why would you do the same in the db?

This is a normal use case in document management systems:

You have a class Document with some fixed fields like createDate, author etc.
And you have arbitrary metadata like invoiceNo and customer for an invoice or employee for a payslip.

These arbitrary metadata maybe stored as a Map-Object which is nothing more than a key-value-pair.
This has to be stored in the database.

It must be possible to create "on-the-fly" new subtypes of Documents without writing new classes or creating new tables.

This is where the problem comes from. Received on Tue Sep 09 2008 - 04:33:41 CDT