Multiple Inheritance with Entity Framework with TPH

Question

Further to this question: http://stackoverflow.com/questions/1877411/entity-framework-tph-with-multiple-abstract-inheritance and VS.2008 sp1 .net 3.5 c#

I decided to add Organizations and a School. Organization(abstract) inherits from Party, and School(concrete) inherits from Organization.

I get the error:

Error   1   Error 3034: Problem in Mapping Fragments starting at lines 73, 93: Two entities with different keys are mapped to the same row. Ensure these two mapping fragments do not map two groups of entities with different keys to the same group of rows.
    C:\Users\xxx\Documents\Visual Studio 2008\Projects\TEST\TEST\Model1.edmx    74  29  TEST

I've seen the 3034 errors alot along my travels in EF. But typically they relate to navigational properties. I haven't seen errors like this in inheritence.

Here's my edmx xml:

<?xml version="1.0" encoding="utf-8"?>
<edmx:Edmx Version="1.0"
xmlns:edmx="http://schemas.microsoft.com/ado/2007/06/edmx"&gt;
    <!-- EF Runtime content -->
    <edmx:Runtime>
        <!-- SSDL content -->
        <edmx:StorageModels>
            <Schema Namespace="test_1Model.Store" Alias="Self"
          Provider="System.Data.SqlClient" ProviderManifestToken="2005"
          xmlns:store="http://schemas.microsoft.com/ado/2007/12/edm/EntityStoreSchemaGenerator"
          xmlns="http://schemas.microsoft.com/ado/2006/04/edm/ssdl"&gt;
                <EntityContainer Name="test_1ModelStoreContainer">
                    <EntitySet Name="Student" EntityType="test_1Model.Store.Student"
              store:Type="Tables" Schema="dbo" />
                </EntityContainer>
                <EntityType Name="Student">
                    <Key>
                        <PropertyRef Name="Id" />
                    </Key>
                    <Property Name="Id" Type="int" Nullable="false"
              StoreGeneratedPattern="Identity" />
                    <Property Name="PartyInfo" Type="varchar(max)" Nullable="false" />
                    <Property Name="PersonInfo" Type="varchar(max)" Nullable="true" />
                    <Property Name="StudInfo" Type="varchar(max)" Nullable="true" />
                    <Property Name="OrgInfo" Type="varchar(max)" Nullable="true" />
                    <Property Name="SchoolInfo" Type="varchar(max)" Nullable="true" />
                    <Property Name="TypeOfParty" Type="varchar(max)" Nullable="false" />
                </EntityType>
            </Schema>
        </edmx:StorageModels>
        <!-- CSDL content -->
        <edmx:ConceptualModels>
            <Schema Namespace="test_1Model" Alias="Self"
          xmlns="http://schemas.microsoft.com/ado/2006/04/edm"&gt;
                <EntityContainer Name="test_Entities">
                    <EntitySet Name="PartySet" EntityType="test_1Model.Party" />
                </EntityContainer>
                <EntityType Name="Party" Abstract="true">
                    <Key>
                        <PropertyRef Name="Id" />
                    </Key>
                    <Property Name="Id" Type="Int32" Nullable="false" />
                    <Property Name="PartyInfo" Type="String" Nullable="false"
              MaxLength="Max" Unicode="false" FixedLength="false" />
                </EntityType>
                <EntityType Name="Person" BaseType="test_1Model.Party" Abstract="true" >
                    <Property Name="PersonInfo" Type="String" Nullable="false" />
                </EntityType>
                <EntityType Name="Student" BaseType="test_1Model.Person" >
                    <Property Name="StudInfo" Type="String" Nullable="false" />
                </EntityType>
                <EntityType Name="Organization" BaseType="test_1Model.Party" Abstract="true" >
                    <Property Name="OrgInfo" Type="String" Nullable="false" />
                </EntityType>
                <EntityType Name="School" BaseType="test_1Model.Organization" >
                    <Property Name="SchoolInfo" Type="String" Nullable="false" />
                </EntityType>
            </Schema>
        </edmx:ConceptualModels>
        <!-- C-S mapping content -->
        <edmx:Mappings>
            <Mapping Space="C-S"
          xmlns="urn:schemas-microsoft-com:windows:storage:mapping:CS">
                <EntityContainerMapping
            StorageEntityContainer="test_1ModelStoreContainer"
            CdmEntityContainer="test_Entities">
                    <EntitySetMapping Name="PartySet">
                        <EntityTypeMapping TypeName="IsTypeOf(test_1Model.Party)">
                            <MappingFragment StoreEntitySet="Student">
                                <ScalarProperty Name="PartyInfo" ColumnName="PartyInfo" />
                                <ScalarProperty Name="Id" ColumnName="Id" />
                            </MappingFragment>
                        </EntityTypeMapping>
                        <EntityTypeMapping TypeName="IsTypeOf(test_1Model.Person)">
                            <MappingFragment StoreEntitySet="Student">
                                <ScalarProperty Name="Id" ColumnName="Id" />
                                <ScalarProperty Name="PersonInfo" ColumnName="PersonInfo" />
                            </MappingFragment>
                        </EntityTypeMapping>
                        <EntityTypeMapping TypeName="test_1Model.Student">
                            <MappingFragment StoreEntitySet="Student">
                                <ScalarProperty Name="Id" ColumnName="Id" />
                                <ScalarProperty Name="StudInfo" ColumnName="StudInfo" />
                                <ScalarProperty Name="PersonInfo" ColumnName="PersonInfo" />
                                <ScalarProperty Name="PartyInfo" ColumnName="PartyInfo" />
                                <Condition ColumnName="TypeOfParty" Value="STUDENT" />
                            </MappingFragment>
                        </EntityTypeMapping>
                        <EntityTypeMapping TypeName="IsTypeOf(test_1Model.Organization)">
                            <MappingFragment StoreEntitySet="Student">
                                <ScalarProperty Name="Id" ColumnName="Id" />
                                <ScalarProperty Name="OrgInfo" ColumnName="OrgInfo" />
                            </MappingFragment>
                        </EntityTypeMapping>
                        <EntityTypeMapping TypeName="test_1Model.School">
                            <MappingFragment StoreEntitySet="Student">
                                <ScalarProperty Name="Id" ColumnName="Id" />
                                <ScalarProperty Name="OrgInfo" ColumnName="OrgInfo" />
                                <ScalarProperty Name="PartyInfo" ColumnName="PartyInfo" />
                                <ScalarProperty Name="SchoolInfo" ColumnName="SchoolInfo" />
                                <Condition ColumnName="TypeOfParty" Value="SCHOOL" />
                            </MappingFragment>
                        </EntityTypeMapping>
                    </EntitySetMapping>
                </EntityContainerMapping>
            </Mapping>
        </edmx:Mappings>
    </edmx:Runtime>
    <!-- EF Designer content (DO NOT EDIT MANUALLY BELOW HERE) -->
    <edmx:Designer xmlns="http://schemas.microsoft.com/ado/2007/06/edmx"&gt;
        <edmx:Connection>
            <DesignerInfoPropertySet>
                <DesignerProperty Name="MetadataArtifactProcessing"
        Value="EmbedInOutputAssembly" />
            </DesignerInfoPropertySet>
        </edmx:Connection>
        <edmx:Options>
            <DesignerInfoPropertySet>
                <DesignerProperty Name="ValidateOnBuild" Value="true" />
            </DesignerInfoPropertySet>
        </edmx:Options>
        <!-- Diagram content (shape and connector positions) -->
        <edmx:Diagrams>
            <Diagram Name="SqlServer_Model" >
                <EntityTypeShape EntityType="test_1Model.Party" Width="1.5" PointX="1.25" PointY="3.25" Height="1.4033821614583326" />
                <InheritanceConnector EntityType="test_1Model.Person" ManuallyRouted="false">
                    <ConnectorPoint PointX="2" PointY="4.6533821614583326" />
                    <ConnectorPoint PointX="2" PointY="5.75" />
                </InheritanceConnector>
                <EntityTypeShape EntityType="test_1Model.Organization" Width="1.5" PointX="3.875" PointY="5.625" Height="1.2110807291666665" />
                <InheritanceConnector EntityType="test_1Model.Organization">
                    <ConnectorPoint PointX="2.75" PointY="3.9516910807291663" />
                    <ConnectorPoint PointX="4.625" PointY="3.9516910807291663" />
                    <ConnectorPoint PointX="4.625" PointY="5.625" />
                </InheritanceConnector>
                <EntityTypeShape EntityType="test_1Model.School" Width="1.5" PointX="3.875" PointY="7.875" Height="1.2110807291666657" />
                <InheritanceConnector EntityType="test_1Model.School">
                    <ConnectorPoint PointX="4.625" PointY="6.8360807291666665" />
                    <ConnectorPoint PointX="4.625" PointY="7.875" />
                </InheritanceConnector>
            </Diagram>
        </edmx:Diagrams>
    </edmx:Designer>
</edmx:Edmx>

Answer 1

You seem to be trying to do table-per-hierarchy mapping (because I see only one table in your SSDL), but I don't see that you have set up a discriminator mapping in the CSDL. There should be a Condition node, like this:

            <Condition ColumnName="NotificationType" Value="Announcement"/>

In short, if you are trying to use a table per hierarchy mapping, you should review the instructions for configuring this and follow them, because you have not completed all of the steps.

If, on the other hand, you intend to do table per type mapping, then you seem to have missed a couple of tables when you updated from your database.