It is widely recognized that there exists a large class of applications for which data modeling capabilities of relational systems are too limited. The current directions in database research and developments are towards object-oriented DBMSs, active knowledge-based management systems and multimedia databases. The third generation of post-relational databases will require larger datasets, enhanced capabilities in data type, multimedia support, complex objects, rule processing and archival storage. The objective of this book is to investigate the trend of the recent database software in various paradigms. These chapters will bring together database practitioners, researchers and vendors to enable them to better discuss the requirements and challenges of post-relational systems: object-oriented databases, knowledge-based databases and multimedia databases. These international contributions to the 7th Hong Kong Computer Society Conference have been carefully reviwed and edited to provide an indispensable volume for further reference.