Connecting Business Objects to Relational Databases

Abstract

These patterns describe how to implement business objects so that they can be mapped to non objectoriented databases. There is an impedance mismatch between these technologies since objects consist of both data and behavior while a relational database consists of tables and relations between them. Although it is impossible to completely eliminate this impedance mismatch, you can minimize it by following the proper patterns. The proper patterns hide persistence from the developer so that effort can be spent on understanding the domain rather than in making objects persistent. 2 Introduction Developers of object-oriented systems that use a relational database usually spend a lot of time making objects persistent. This is because of a fundamental impedance mismatch 1 between the two paradigms; objects consist of both data and behavior and often have inheritance while relational databases consist of tables, relations and basic predicate calculus functions to return desired values. On...