Data Access Layer

The data access layer [10] allows an entire encapsulation of all interactions with the database. This considerably simplifies the interaction with the database. Additionally the database is protected as direct access to it is prohibited and the integration of the database into the application is eased.

The data access layer is decomposed into three parts. One part is reponsible for managing the table `users', the second for managing the table containing the tasks including the XML. The last part accounts for the lecture of the table `tasks' when detailed information is required. This detailed information is entirely stored in the XML part of the database.

To retrieve the data stored as XML from the database, XPATH [9] is used.