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TwinFeats Java Object Database
JavaDoc for twinfeats.db or you can download just the runtime package db.jar
January 16, 1999, updated March 10, 2001
The package twinfeats.db comprises a simple java object database server. General serializable objects can be put into the database and later retrieved in a variety of ways through the provided API. Keep in mind that I wrote this package, like so many of the other twinfeats packages, for my own specific use. While it is reasonably generic it is also a minimal implementation written with the purpose to help with the various features I keep adding to TwinFeats and other sites. It's also important to note that I had virtually no experience with any databases prior to writing this package so while you should find the API fairly full featured it might be somewhat unorthodox if you've used more traditional databases before.
There are three types of databases in this package, in inheritence order: Database, MultiDatabase, and GeneralDB. Database provides the backbone of the API including adding, updating, removing, and searching records in the database. MultiDatabase extends this functionality just a little bit further with sequences, which are unordered named lists of database records. Finally GeneralDB provides a simple framework for a relational database along with the TableKey class.
It is important that the javadocs for this package be read carefully, and keep in mind that this API has evolved over about 3 years and so you will find it to be quite diverse. However with that diversity comes a degree of complexity, and in some cases seeming inconsistency. If you have any questions, don't hesitate to contact me!
There is a small sample application available that illustrates a number of the key features of using the twinfeats.db package. This app shows how to use a GeneralDB to create two tables, one for a Contact class and one for a Task class. It also shows how to perform simple relational database functionality between the Contact database table and the Task database table. Finally, this example shows how to do simple automatic indexing via JavaBean properties as well as index lookup and a general database search.