Introduction

Welcome to Dimensional Data Warehousing with MySQL: A Tutorial.

Data warehousing enables unified information delivery by collecting data from various operational and administrative information systems already in operation and possibly from external data sources. The data from these sources are integrated, cleaned and transformed, and stored for easier access than if the data has to be read directly from the sources.

The data structure in a data warehouse allows you to store current and historical data. Current information is needed for operational activities, mostly for producing regular hardcopy or online reports. Historical data, unlikely to be readily available from the source, provides the business with information for time-based analysis such as tracking, trend analysis, and comparison, all of which are important for long-term planning and strategic decision-making.

Integrating data from multiple sources, storing and accumulating the data regularly, and providing fast access to it require design and development techniques that are different from techniques used in operational and administrative systems. This book is all about data warehousing design and development techniques. It covers most commonly used techniques in the phases of building a data warehouse. More important, this book provides an easy to follow tutorial for developing a real world data warehouse.

What This Book Is About and What It Is Not

Dimensional Data Warehousing with MySQL is a practical book. You will use MySQL, but this book is not about MySQL. The book does not discuss hardware infrastructural aspects either.

The focus of this book is on data warehouse design and development techniques. The book however is not about techniques on managing development projects, development methodologies, or leading developments.

The book uses an example data warehouse development to show the implementation of the techniques. The data model and the SQL scripts are included and can be adapted to be used in real-world data warehouse development. The scripts have been tested on MySQL 5.0.21 running on Windows XP Professional SP2.

In addition, this book does not specifically discuss the following topics.

• The concepts of data warehousing

• SQL

• MySQL