This book discusses the application of some Artificial Intelligence (AI) technologies to database systems. The integration of AI technology and database management has developed into an important research topic, and many AI methods, such as logic programming, natural language understanding, knowledge-bases, etc., have been applied to the development of intelligent database systems capable of deduction, natural language query understanding, cooperative query answering, and substantial query guidance. In this book, the authors review some knowledge-base assisted database access techniques, incorporating techniques to form a new kind of database front-end. The results of these applications are summarized and explained.