What type of DB model is this?

Hi,

I am writing a program in Java which deals with a data structure which is hierarchical as follows, with levels A, B etc representing a level in the hierarchy:

MyDatabase contains 12 level A items
Each level A item contains between 1 and 4 level B items Each level B item contains 1 level C item Each level C item contains between 1 and 4 level D items Each level D item contains between 1 and 20 level E items.

At each level of the database, all that is stored is some text information. Levels A - C contain 1 word descriptions, whilst levels D and E contain short sentences.

The other complication is that the database I use is really a master database and what the software allows each user to do is to create a subset copy of this database which they can then edit. The way I have worked this in the past is when the user is to give each item at each level a key, and then when the user creates the subset database, simply store a file of all of the keys. I suppose the user database could be described as a series of links to the master DB.

But this gives rise to certain problems, namely what if changes are made to the master database - they need to be reflected in the user database, but changes in the user copy should not affect the master copy.

I hope this makes some sense. My DB theory is pretty poor (I would guess that's obvious). All I am looking for are some tips as to what kind of DB model I should be using.

Many thanks

Mark Received on Tue Aug 14 2001 - 18:48:59 CEST