Enumerations have been supported in Entity Framework 5 – however Enums are not yet supported in WCF Data Services, which means you still need to handle them explicitly when writing OData services.
EF 5 was recently released, and it included one of the most awaited features in Enum Support. However, WCF Data Services 5.0 doesn’t support Enum yet. Since WCF Data Services uses the same Entity Data Model that Entity Framework uses, if you use an EF model that includes Enums with WCF Data Services, it now leads to an arcane error.
This is a breaking change, since models with Enums in the EF model were just ignored earlier without failing.
According to the WCF Data Services team, using NotMapped property attribute is a possible work-around. However, the NotMapped attribute prevents the property to being mapped to an underlying database column, which means we would effectively stop using the newly added Enum Support in Entity Framework as well. Support for Enums is now the most-requested feature on the WCF Data Services user forum.
WCF Data Services enables the creation and consumption of OData web services using REST semantics.