Data access architecture in object oriented applications using design patterns

This paper describes the data access architecture in a modern object-oriented application. Complex application solutions have multiple, parallel data sources. Each data source has many specific properties and ways for data access. This architecture, by using the already tried solutions, ensures a simple and flexible way to access the different data sources. It also describes the singleton, data access object and abstract the factory patterns and their interaction in achieving the flexible and scalable data access architecture.