This is not a book about advanced SQL. It is not a book about the Oracle optimizer and diagnostic tools. And it is not a book about relational calculus, predicate logic, or set theory. This book is a SQL primer. It is meant to help you learn Oracle SQL by yourself. It is ideal for self-study, but it can also be used as a guide for SQL workshops and instructor-led classroom training.
This is a practical book; therefore, you need access to an Oracle environment for hands-on exercises. All the software that you need to install Oracle Database on either Windows or Linux for learning purposes is available free of charge from the Oracle Technology Network (OTN)
The main objective of this book is the combination of usability and affordability. The official Oracle documentation offers detailed information in case you need it. Therefore, it is a good idea to have the Oracle manuals available while working through the examples and exercises in this book. The Oracle documentation is available online from the OTN website mentioned earlier in this introduction. You can access that documentation in HTML form, or you can download PDF copies of selected manuals.
The focus of this book is using SQL for data retrieval. Data definition and data manipulation are covered in less detail. Security, authorization, and database administration are mentioned only for the sake of completeness in the "Overview of SQL" section of Chapter 2.
Throughout the book, we use a case consisting of seven tables. These seven tables contain information about employees, departments, and courses. As Chris Date, a well-known guru in the professional database world, said during one of his seminars, "There are only three databases: employees and departments, orders and line items, and suppliers and shipments."
