What is the difference between the Enterprise, Standard and Personal Editions of Oracle?
Oracle Enterprise Edition:
Enterprise Edition is the full (top of the range) version or the Oracle Database Server. Options like RAC, Partitioning, Spatial, etc. can be purchased separately to enhance the functionality of the database.
Oracle Standard Edition:
Standard Edition is designed for smaller businesses and enterprises. It offers a subset of the features/ functionality implemented in Enterprise Edition. Database options like Data Guard, Partitioning, Spatial, etc. is not available with Standard Edition (from 10g one can use RAC with Standard Edition). Standard Edition can only be licensed on servers with a maximum capacity of four processors.
Oracle Standard Edition One:
Standard Edition One is a low cost, entry-level version of the Oracle Standard Edition database server. Standard Edition One can only be licensed on small servers with a maximum capacity of two processors.
Oracle Personal Edition:
Personal Oracle is a single user version of the database server. It is mostly the same as Enterprise Edition, but doesn't support advanced options like RAC, Streams, XMLDB, etc.
Oracle Light is a database engine that can be used on mobile platforms like cell phones and PDA's.
Express Edition (XE) is a free, downloadable version of the Oracle database server. Oracle XE can only be used on single processor machines. It can only manage up to 4 GB of data and 1 GB of memory. ISVs can embed XE in 3rd party products and redistribute it freely.
Oracle10g Database Licensing Guide
(Part of the Oracle 10g Documentation Set)
Oracle9i Database New Features Guide
Chapter 5: Database Feature and Option Availability