A tag for pages describing databases and database technology. Includes Relational, Hierarchical, OO, and other database technologies.
This tag is also used for pages about Object Persistence, even though that concept is not necessarily synonomous with "database technology".
Click on the "Category Database" title to see a list of pages that fit into this category.
Related categories: Category Query Language Category Tql Category Relational Database Category Persistence
The first things first...
Implementation aspects
Multiversion Concurrency Control - used by Fire Bird (formerly Inter Base), Oracle, Gemstone, My Sql's InnoDB engine, and Postgre Sql
Snapshot Isolation - ditto
Object -vs- Relational discussion
Object Relational Impedance Mismatch (...and if it exists or not. ;-)
"Object Database vs. Object-Relational Databases" by Steve Mc Clure of Jasmine -- www.cai.com 
Database Paradigms
Relational Database Discussion
Portable Sql (patterns for how to do it)
Relational Database Products
(...possibly with some "object oriented" features)
Oracle: Oracle Database
Sybase System 10/11
IBM: DB2 (Db Two)
UniSQL/X
Unisys: OSMOS
Red Brick (specialized for Data Warehousing)
AxionDB : Axion Database
NiLOSTEP : Xl Sql
Enterprise Db (Oracle Database clone based on Postgre Sql)
See also en.wikipedia.org
Relational Database Languages
Tql Roadmap (experimental)
Object Oriented Database Discussion
Architecture And Object Databases (...with comments on serveral of the following OODB servers.)
Object Oriented Database Products
db4objects: db4o (Dee Bee Four Oh) www.db4o.com (open source)
Gemstone: Gem Stone
O2 (see also Oh Two Unit)
Objectivity: Objectivity/DB
Versant: VersantODBMS
Object-Relational Mapping
Bold
Enterprise Objects Framework (part of Web Objects)
Traditional Hierarchical Database Products
IBM: IMS (Ibm Ims)
Other Database Products
End User Database or Desktop Database A DBMS, including a user interface intended for non technical users.
Techniques
Boyce Codd Normal Form (BCNF)
Fifth Normal Form AKA Project-join normal form (PJ/NF)
Speculation
See original on c2.com