FetchPlans and FetchGroups provide you with a mechanism, where you can specify the retrieval of only those fields that are required from the database, in as few database calls as possible. Thus you could optimize the queries executed by OpenAccess ORM when retrieving more complex data.

A default FetchGroup is created for each class, and it will retrieve all the fields that are of basic type or single reference type (only the id of the referenced object will be retrieved), as a result of a query or while resolving a reference.

Telerik OpenAccess ORM allows you to specify fetch groups in a visual way from the "Forward Mapping" dialog. You don't need to change your queries (OQL or LINQ) and put information about your fetch groups, which makes things easier for maintenance.

This example demonstrates how to use a single query to retrieve fields from different databases by using FetchPlans and FetchGroups. It retrieves all orders and in addition fetches the CompanyName and LastName for each Customer. By default, such operation would require the execution of more queries as data should be retrieved from several tables. Using Telerik OpenAccess ORM, you can include the required related fields in a fetch group and retrieve the records in a single query.