The first dedicated discussion of database refactoring, showing data professionals how to use refactoring, test-driven, and other agile techniques for evolutionary database development. The book explains in detail the process, strategy and deployment of database reconstruction through many practical examples. . The first 5 chapters of this book introduce the basic ideas and techniques of evolutionary database development, and the last 6 chapters describe each type of reconstruction in detail, including structure, data quality, referential integrity, architecture, and method reconstruction; in addition, it also describes Conversion techniques that do not fall within the scope of refactoring are included. The sample codes in the book are written in Java, Hibernate, and Oracle code. The codes are very simple, and readers can convert them into C#, C++, or Visual Basic code without any difficulty. The value of refactoring is unquestionable and has been proven in many projects. Refactoring helps software professionals improve system design and its maintainability, scalability, and performance.