Add the following types to the list of built-in types: -Edm.PrimitiveType -Edm.ComplexType -Edm.EntityType Conceptually, these are the (default) abstract base types for primitive types, complex types, and entity types, respectively, and can be used anywhere the corresponding type can be used, except: 1) you can't use Edm.EntityType as the type for a named top-level entity in your container. 2) you can't use Edm.EntityType as the type of an entityset (because all entities in an entityset must currently have the same key fields to uniquely identify it within the set) 3) in the base attribute of an EntityType/ComplexType definition (it's assumed) Examples of where you can use these abstract base types, as appropriate: -as the type of a collection (i.e., Collection(Edm.EntityType) in a navigation property) -in a TypeDefinition -in a Property definition (Edm.ComplexType, Edm.PrimitiveType, Collection(Edm.ComplexType), Collection(Edm.PrimitiveType) -in a navigation property definition (Edm.EntityType, Collection(Edm.EntityType) -in a Parameter definition -as a Function returntype -in a Term definition Note that you can cast the results of a function, for example, to a particular type in order to access it's properties (i.e., in a $filter, $expand, or $orderby). For example: ~MyFunctionThatReturnsAnyEntityType()/MyModel.Customer?$filter=FirstName eq 'Ralf' This filters the results to only those that match the specified type and casts the results to that type. Accepted: https://www.oasis-open.org/committees/download.php/48097/odata-meeting-23_on-20130130_31-F2F-minutes.html#odata-16

https://www.oasis-open.org/committees/download.php/48171/odata-core-v1.0-wd01-part3-csdl-2013-02-07-RH.doc https://tools.oasis-open.org/version-control/browse/wsvn/odata/trunk/spec/schemas/csdl.xsd?rev=175 Accepted: https://www.oasis-open.org/committees/download.php/48269/odata-meeting-25_on-20130214-minutes.html#odata-16