DefiningQuery Element (EntityContainer SSDL)
The DefiningQuery element in store schema definition language (SSDL) defines a query that maps to data-store views through client-side projection within the Entity Data Model (EDM). Such mappings are read-only. Without client-side projection, users map all store-view columns and provide a dummy update customization.
A narrow projection of system views is used to generate a default EDM. The defining query is read-only. Entity Data Model tools use mapping artifacts to start workflow. For more information, see How to: Add a Defining Query.
The following SSDL syntax shows the declaration of an EntitySet followed by the DefiningQuery element that contains a query used to retrieve the view.
<Schema> <EntitySet Name="Tables" EntityType="Self.STable"> <DefiningQuery> SELECT TABLE_CATALOG, 'test' as TABLE_SCHEMA, TABLE_NAME FROM INFORMATION_SCHEMA.TABLES </DefiningQuery> </EntitySet> </Schema>
The support for stored procedures in the ADO.NET Entity Framework can be used to enable read-write scenarios over arbitrary views that the user knows how to update. Either a store-view or an Entity SQL view can be used as the base table for retrieving data and for change processing by stored procedures.