Elemento ReferentialConstraint (EntityContainer CSDL)

Nel modello EDM (Entity Data Model) l'elemento ReferentialConstraint in CSDL (Conceptual Schema Definition Language) specifica gli elementi Principal Role e Dependent Role di un'associazione. I vincoli referenziali influiscono sul comportamento degli oggetti correlati in un ObjectContext. Per ulteriori informazioni, vedere Vincoli referenziali (Entity Framework).

Nell'associazione seguente il tipo VendorAddress dipende dal tipo Address. Un oggetto Address può essere correlato a più oggetti VendorAddress perché VendorAddress connette semplicemente un oggetto Address con un oggetto Vendor. Un oggetto Vendor può avere più di un oggetto Address.

  <Association Name="FK_VendorAddress_Address_AddressID">
    <End Role="Address" Type="Adventureworks.Address" Multiplicity="1" />
    <End Role="VendorAddress" Type="Adventureworks.VendorAddress" Multiplicity="*" />
    <ReferentialConstraint>
      <Principal Role="Address">
        <PropertyRef Name="AddressID" />
      </Principal>
      <Dependent Role="VendorAddress">
        <PropertyRef Name="AddressID" />
      </Dependent>
    </ReferentialConstraint>
  </Association>

<EntityType Name="VendorAddress">
    <Key>
      <PropertyRef Name="VendorID" />
      <PropertyRef Name="AddressID" />
    </Key>
    <Property Name="VendorID" Type="Int32" Nullable="false" />
    <Property Name="AddressID" Type="Int32" Nullable="false" />
    <Property Name="ModifiedDate" Type="DateTime" Nullable="false" />
    <NavigationProperty Name="Address"
     Relationship="Adventureworks.FK_VendorAddress_Address_AddressID"
       FromRole="VendorAddress" ToRole="Address" />
    <NavigationProperty Name="AddressType"
Relationship="Adventureworks.FK_VendorAddress_AddressType_AddressTypeID
   " FromRole="VendorAddress" ToRole="AddressType" />
    <NavigationProperty Name="Vendor"
     Relationship="Adventureworks.FK_VendorAddress_Vendor_VendorID"
     FromRole="VendorAddress" ToRole="Vendor" />
  </EntityType>

<EntityContainer Name="AdventureworksContext">

   <EntitySet Name="VendorAddress" 
          EntityType="Adventureworks.VendorAddress" />

  <AssociationSet Name="FK_VendorAddress_Address_AddressID"
     Association="Adventureworks.FK_VendorAddress_Address_AddressID">
      <End Role="Address" EntitySet="Address" />
      <End Role="VendorAddress" EntitySet="VendorAddress" />
  </AssociationSet>

</EntityContainer>

Vedere anche

Concetti

Elemento AssociationSet (EntityContainer CSDL)