Structure and Analysis of edmx Files (2)

The Entity Designer of Visual Studio 2008 stores its data in an XML file with the extension .edmx. In the first part of this series I covered the Storage Model.

The Conceptual Model describes the EntitySets, Entities, AssociationSets and Associations as .Net classes and attributes in the xmlns:edm and xmlns:a schemas

• xmlns:edm=”http://schemas.microsoft.com/ado/2006/04/edm”
• xmlns:a=”http://schemas.microsoft.com/ado/2006/04/codegeneration”

    <edmx:ConceptualModels>
      <edm:Schema Namespace="My.Namespace.Entities" Alias="Self" xmlns="http://schemas.microsoft.com/ado/2006/04/edm">
        <edm:EntityContainer Name="MyEntities">
          <edm:EntitySet Name="TableFooSet" EntityType="My.Namespace.Entities.TableFoo" />
          <edm:AssociationSet Name="FK_TABLEFOO_TABLEBAR" Association="My.Entities.FK_TABLEFOO_TABLEBAR">
            <edm:End Role="TableBar" EntitySet="TableBarSet" />
            <edm:End Role="TableFoo" EntitySet="TableFooSet" />
          </edm:AssociationSet>
          <edm:FunctionImport Name="SPBarFromFoo">
            <edm:Parameter Name="FooID" Mode="In" Type="Int32" />
            <edm:Parameter Name="BarID" Mode="InOut" Type="Int32" />
          </edm:FunctionImport>
        </edm:EntityContainer>

The Entity Container lists all sets. Then the entity description is listed in terms of Properties (columns) and Navigational Properties (foreign keys). NavigationalProperties are present in both tables of a foreign key relation:

        <edm:EntityType Name="TableFoo">
          <edm:Key>
            <edm:PropertyRef Name="ID" />
          </edm:Key>
          <edm:Property Name="ID" Type="Int32" Nullable="false" />
          <edm:Property Name="Serial" Type="String" Nullable="false"
            MaxLength="20" Unicode="true" FixedLength="false" />
          <edm:NavigationProperty Name="Bar" Relationship="My.Namespace.Entities.FK_TABLEFOO_TABLEBAR"
            FromRole="TableFoo" ToRole="TableBar" />
        </edm:EntityType>
        <edm:Association Name="FK_TABLEFOO_TABLEBAR">
          <edm:End Type="My.Namespace.Entities.TableBar" Role="TABLEBAR"
            Multiplicity="1" />
          <edm:End Type="My.Namespace.Entities.TableFoo" Role="TABLEFOO"
            Multiplicity="*" />
        </edm:Association>

The xmlns:a schema is used if property getter or setter have been assigned non-public visibility:

<edm:NavigationProperty Name="TABLEBAR" 
  Relationship="My.Namespace.Entities.FK_TABLEBAR_TABLEBLAH" 
  FromRole="TABLEBLAH" ToRole="TABLEBAR" 
  a:GetterAccess="Private" a:SetterAccess="Private" />

The end of the Conceptual Model

      </edm:Schema>
    </edmx:ConceptualModels>

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