PL/SQL is Oracle's procedural language extension to SQL, for use in those cases where SQL functionality on its own isn't sufficient. Ubiquitous across the various Oracle products, PLSQL has seen many different versions and supports development both server-side in the database and client-side in application code.

The book starts with an overview of the different versions available and then throughout, when features are introduced, it's made clear if there are restrictions for use across versions. This works well, as the progression is from fundamentals to advanced features and as you would expect the Oracle 8 features are dealt with towards the end.

The author takes the trouble early on to discuss coding style in general and the reasoning behind his personal style, before the detailed discussion of language features. The examples used in the book are useful and the comments on approach show real experience. This evidence of living in the real world is added to in the later stages of the book with sections on design, debugging and tuning.

The book is suitable for use both as a learning aid and as a reference. It's my first choice for answering PL/SQL questions and certainly much more useful than the Oracle supplied documentation.