Oracle

Documentation for all versions:

http://www.oracle.com/technology/documentation/index.html

Oracle 10g Release 2 documentation

http://www.oracle.com/pls/db102/homepage

Oracle 9i documentation

http://www.oracle.com/pls/db92/db92.homepage

Catalog and dictionary views

http://www.oracle.com/pls/db92/db92.catalog_views?remark=homepage