Structure and Analysis of edmx Files (1)

The Entity Designer of Visual Studio 2008 stores its data in an XML file with the extension .edmx.

The file contains the Storage Model, the Conceptual Model, and Mappings between both models, and also layout information of the diagram. (The inclusion of layout data in a model file is really a conceptual mess).

Each section has its one or more XML namespaces. The ones I found necessary for parsing the XML data are:

• xmlns:xsl=”http://www.w3.org/1999/XSL/Transform”
• xmlns:edmx=”http://schemas.microsoft.com/ado/2007/06/edmx”
• xmlns:store=”http://schemas.microsoft.com/ado/2007/12/edm/EntityStoreSchemaGenerator”
• xmlns:ssdl=”http://schemas.microsoft.com/ado/2006/04/edm/ssdl”
• xmlns:cs=”urn:schemas-microsoft-com:windows:storage:mapping:CS”
• xmlns:edm=”http://schemas.microsoft.com/ado/2006/04/edm”
• xmlns:a=”http://schemas.microsoft.com/ado/2006/04/codegeneration”

This is the hierarchical structure of edmx. The first part describes the Storage Model which contains the selected objects from a SQL Server database: Tables, Views, Stored Procedures.

<?xml version="1.0" encoding="utf-8"?>
<edmx:Edmx >
  <!-- EF Runtime content -->
  <edmx:Runtime>
    <!-- SSDL content -->
    <edmx:StorageModels>
      <ssdl:Schema Namespace="My.Namespace.Entities.Store">
        <ssdl:EntityContainer Name="MyEntitiesStoreContainer">
          <ssdl:EntitySet Name="MY_TABLE_NAME"
            EntityType="My.Namespace.Entities.Store.MY_TABLE_NAME"
            store:Type="Tables" Schema="dbo" />

          <ssdl:EntitySet Name="MY_VIEW_NAME"
            EntityType="My.Namespace.Entities.Store.MY_VIEW_NAME"
            store:Type="Views" store:Schema="dbo"
            store:Name="MY_VIEW_NAME">
            <ssdl:DefiningQuery>SELECT FOO FROM BAR
            </ssdl:DefiningQuery>
          </ssdl:EntitySet>

The foreign keys are listed as Association Sets:

          <ssdl:AssociationSet Name="FK_TABLEFOO_TABLEBAR"
            Association="My.Namespace.Entities.Store.FK_TABLEFOO_TABLEBAR">
            <ssdl:End Role="TABLEBAR" EntitySet="TABLEBAR" />
            <ssdl:End Role="TABLEFOO" EntitySet="TABLEFOO" />
          </ssdl:AssociationSet>
        </ssdl:EntityContainer>

After the Entity Container, all Entity Types and Associations are declared with their names and attributes:

        <ssdl:EntityType Name="TABLEFOO">
          <ssdl:Key>
            <ssdl:PropertyRef Name="ID" />
          </ssdl:Key>
          <ssdl:Property Name="ID" Type="int" Nullable="false" StoreGeneratedPattern="Identity" />
          <ssdl:Property Name="NAME" Type="nvarchar" Nullable="false" MaxLength="150" />
          <ssdl:Property Name="BAR_ID" Type="int" Nullable="true" />
        </ssdl:EntityType>
        <ssdl:Association Name="FK_TABLEFOO_TABLEBAR">
          <ssdl:End Role="TABLEBAR" Type="My.Namespace.Entities.Store.TABLEBAR"
            Multiplicity="1" />
          <ssdl:End Role="TABLEFOO" Type="My.Namespace.Entities.Store.TABLEFOO"
            Multiplicity="*" />
          <ssdl:ReferentialConstraint>
            <ssdl:Principal Role="TABLEBAR">
              <ssdl:PropertyRef Name="ID" />
            </ssdl:Principal>
            <ssdl:Dependent Role="TABLEFOO">
              <ssdl:PropertyRef Name="BAR_ID" />
            <ssdl:/Dependent>
          </ssdl:ReferentialConstraint>
        </ssdl:Association>

Stored Procedures can also be included in the Storage Model:

        <ssdl:Function Name="SP_BAR_FROM_FOO" Aggregate="false" BuiltIn="false" 
          NiladicFunction="false" IsComposable="false" 
          ParameterTypeSemantics="AllowImplicitConversion" Schema="dbo">
          <ssdl:Parameter Name="FOO_ID" Type="int" Mode="In" />
          <ssdl:Parameter Name="BAR_ID" Type="int" Mode="InOut" />
        </ssdl:Function>

The end of the Storage Model section

      </ssdl:Schema>
    </edmx:StorageModels>