1. The material on optimization has been expanded, by including a discussion of the System R approach to optimization, tableau-based methods, and optimization in the distributed environment.
   
2. There is a discussion of universal relation systems, which are relational database systems that support a user view that looks like a single relation.
   
3. Concurrency control by "optimistic," or timestamp-based methods has been introduced.
   
4. Distributed systems are covered, both for optimization issues and concurrency control.
   
5. A discussion of data structures for range queries appears.
   
6. There is an introduction to generalized dependencies and their inference.

The second edition was prepared using Don Knuth's TEX typesetting system.