Entity Data Model Mapping Scenarios (Application Scenarios)

Entity splitting

In this mapping scenario, properties from a single entity in the conceptual model are mapped to columns in two or more underlying tables. In this scenario, the tables must share a common primary key. For more information, see How to: Define a Model with Single Entity Mapped to Two Tables.

Horizontal partitioning in the conceptual model

In this mapping scenario, multiple entity types in the conceptual model that have the same properties are mapped to a single table. A condition clause is used to specify which data in the table belongs to which entity type. This mapping is similar to table-per-hierarchy inheritance mapping. For more information, see How to: Define a Model with Table-per-Hierarchy Inheritance.

Table-per-type inheritance

In this mapping scenario, all types are all mapped to individual tables. Properties that belong solely to a base type or derived type are stored in a table that maps to that type. For more information, see How to: Define a Model with Table-per-Type Inheritance (Entity Framework).

Multiple entity sets per type

In this mapping scenario, a single entity type is expressed in two or more separate entity sets in the conceptual model. Each entity set is mapped to a separate table in the storage model. For more information, see How to: Define a Model with Multiple Entity Sets per Type (Entity Framework).

Function import mapping

In this scenario, a stored procedure in the storage model is mapped to a FunctionImport element in the conceptual model. This function is executed to return entity data using the mapped stored procedure. For more information, see How to: Define a Model with a Stored Procedure (Entity Framework).

Defining query mapping

In this scenario, a query is defined in the storage model that represents a table in the data source. The query is expressed in the native query language of the data source, such as Transact-SQL, when mapping to a SQL Server database. This DefiningQuery element is mapped to an entity type in the conceptual model. The query is defined in the store-specific query language. For more information, see How to: Add a Defining Query. When you use a defining query, updates cannot be persisted to the data source using the standard update process. Updates can be made by defining modification function mappings. For more information, see Stored Procedure Support (Entity Framework).

AssociationSet mapping

Associations define relationships between entities. In a simple mapping with a one-to-one or one-to-many association, associations that define relationships in the conceptual model are mapped to associations in the storage model. The following more advanced association set mappings are also supported:

• Many-to-many associations. Both ends of the association are mapped to a link table in the storage model.

• Self association. This supports an association between two entities of the same type, such as an Employee with an association to another Employee.

• Associations between derived types. This mapping supports an association between a derived type in one hierarchy and a derived type in a second hierarchy. For more information, see How to: Define a Model with Associations Between Derived Types (Entity Framework).

For more information, see Association (EDM).