Data access layer: Difference between revisions

Revision as of 09:00, 8 May 2008

Revision as of 17:58, 21 November 2008

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Also, business logic methods from an application can be mapped to the Data Access Layer. So, for example, instead of making a query into a database to fetch all users from several tables the application can call a single method from a DAL which abstracts those database calls.

Applications using a data access layer can be either database-dependent or database-independent—if the data access layer supports multiple databases, the application becomes able to use whatever databases the DAL can talk to. In either circumstance, having a data access layer provides a centralized ___location for all calls into the database, and thus makes it easier to port the application to other database systems (assuming that 100% of the database interaction is done in the DAL for a given application).

Data Access layer will make project database independent.

[[Object-Relational Mapping]] tools provide data layers in this fashion, following the [[Active record pattern|active record]] model.