Abstract: Over the last decade, database system products have been extended to provide support for defining, storing, updating, indexing, and retrieving complex data with full transaction semantics. Oracle, IBM, Informix and others have used extensibility technology to build database system extensions for text, image, spatial, audio/video, chemical, genetic, and other types of complex data. Currently, we find database systems being deployed in support of e-Commerce. In many cases these e-Commerce database applications use only simple SQL data types to represent items such as office supplies, computers, books, and CDs. There is also a large and important set of e-Commerce applications that employ complex data formats such as EDI, SWIFT, and HL7. The database extensibility features initially developed to support text, spatial and similar forms of complex data are now being used to build e-Commerce applications. Thus, database extensibility technology is evolving into an important mechanism to enable development of e-Commerce systems.