Thirty-five years ago, databases were found only in special research laboratories, where computer scientists struggled with ways to make them efficient and useful, publishing their findings in countless research papers. Today databases are a ubiquitous part of the information technology (IT) industry and business in general. We directly and indirectly use databases every day—banking transactions, travel reservations, employment relationships, website searches, online and offline purchases, and most other transactions are recorded in and served by databases.

As is the case with many fast-growing technologies, industry standards have lagged behind in the development of database technology, resulting in myriad commercial products, each following a particular software vendor’s vision. Moreover, a number of different database models have emerged, with the relational model being the most prevalent. Databases: A Beginner’s Guide examines all of the major database models, including hierarchical, network, relational, object-oriented, and object-relational. This book concentrates heavily on the relational and object-relational models, however, because these are the mainstream of the IT industry and will likely remain so in the foreseeable future.

The most significant challenge in implementing a database is correctly designing the structure of the database. Without a thorough understanding of the problem the database is intended to solve, and without knowledge of the best practices for organizing the required data, the implemented database becomes an unwieldy beast that requires constant attention.