3 Using Your Data Provider with the ADO.NET Entity Framework : Mapping EDM Canonical Functions to Data Source Functions

Mapping EDM Canonical Functions to Data Source Functions
The ADO.NET Entity Framework translates the Entity Data Model (EDM) canonical functions to the corresponding data source functionality for the ADO.NET Entity data provider. The function invocations are expressed in a common form across data sources.
Because these canonical functions are independent of data sources, argument and return types of canonical functions are defined in terms of types in the EDM. When an Entity SQL query uses canonical functions, the appropriate function is called at the data source.
Both null-input behavior and error conditions are explicitly specified for all canonical functions. However, the ADO.NET Entity Framework does not enforce this behavior. Further details are available at:
http://msdn.microsoft.com/en-us/library/bb738626.aspx
For more information about mapping edm canonical functions, refer to the DataDirect Connect Series for ADO.NET User’s Guide.