Question

Added a Database and an Entity Model to my DAL Project.

got an error :

Error :

 +      base    {"Schema specified is not valid. Errors: \r\nMultiple types with the name 'TblRecord' exist in the EdmItemCollection in different namespaces.  Convention based mapping requires unique names without regard to namespace in the EdmItemCollection."}   System.Data.EntityException {System.Data.MetadataException}

---

The Edmx File

<?xml version="1.0" encoding="utf-8"?>
<edmx:Edmx Version="3.0" xmlns:edmx="http://schemas.microsoft.com/ado/2009/11/edmx">
  <!-- EF Runtime content -->
  <edmx:Runtime>
    <!-- SSDL content -->
    <edmx:StorageModels>
      <Schema Namespace="Xz.Business.Matches.Store" Alias="Self" Provider="System.Data.SqlServerCe.4.0" ProviderManifestToken="4.0" xmlns:store="http://schemas.microsoft.com/ado/2007/12/edm/EntityStoreSchemaGenerator" xmlns="http://schemas.microsoft.com/ado/2009/11/edm/ssdl">
        <EntityContainer Name="XzBusinessMatchesStoreContainer">
          <EntitySet Name="Records" EntityType="Xz.Business.Matches.Store.Records" store:Type="Tables" />
        </EntityContainer>
        <EntityType Name="Records">
          <Key>
            <PropertyRef Name="Record" />
          </Key>
          <Property Name="Record" Type="nvarchar" Nullable="false" MaxLength="100" />
          <Property Name="Relations" Type="nvarchar" MaxLength="450" />
        </EntityType>
      </Schema>
    </edmx:StorageModels>
    <!-- CSDL content -->
    <edmx:ConceptualModels>
      <Schema Namespace="Xz.Business.Matches" Alias="Self" p1:UseStrongSpatialTypes="false" xmlns:annotation="http://schemas.microsoft.com/ado/2009/02/edm/annotation" xmlns:p1="http://schemas.microsoft.com/ado/2009/02/edm/annotation" xmlns="http://schemas.microsoft.com/ado/2009/11/edm">
        <EntityContainer Name="RecordzEntities" p1:LazyLoadingEnabled="true">
          <EntitySet Name="Records" EntityType="Xz.Business.Matches.TblRecord" />
        </EntityContainer>
        <EntityType Name="TblRecord">
          <Key>
            <PropertyRef Name="Record" />
          </Key>
          <Property Name="Record" Type="String" Nullable="false" MaxLength="100" Unicode="true" FixedLength="false" />
          <Property Name="Relations" Type="String" MaxLength="450" Unicode="true" FixedLength="false" />
        </EntityType>
      </Schema>
    </edmx:ConceptualModels>
    <!-- C-S mapping content -->
    <edmx:Mappings>
      <Mapping Space="C-S" xmlns="http://schemas.microsoft.com/ado/2009/11/mapping/cs">
        <EntityContainerMapping StorageEntityContainer="XzBusinessMatchesStoreContainer" CdmEntityContainer="RecordzEntities">
          <EntitySetMapping Name="Records">
            <EntityTypeMapping TypeName="Xz.Business.Matches.TblRecord">
              <MappingFragment StoreEntitySet="Records">
                <ScalarProperty Name="Record" ColumnName="Record" />
                <ScalarProperty Name="Relations" ColumnName="Relations" />
              </MappingFragment>
            </EntityTypeMapping>
          </EntitySetMapping>
        </EntityContainerMapping>
      </Mapping>
    </edmx:Mappings>
  </edmx:Runtime>
  <!-- EF Designer content (DO NOT EDIT MANUALLY BELOW HERE) -->
  <Designer xmlns="http://schemas.microsoft.com/ado/2009/11/edmx">
    <Connection>
      <DesignerInfoPropertySet>
        <DesignerProperty Name="MetadataArtifactProcessing" Value="EmbedInOutputAssembly" />
      </DesignerInfoPropertySet>
    </Connection>
    <Options>
      <DesignerInfoPropertySet>
        <DesignerProperty Name="ValidateOnBuild" Value="true" />
        <DesignerProperty Name="EnablePluralization" Value="True" />
        <DesignerProperty Name="IncludeForeignKeysInModel" Value="True" />
        <DesignerProperty Name="CodeGenerationStrategy" Value="None" />
      </DesignerInfoPropertySet>
    </Options>
    <!-- Diagram content (shape and connector positions) -->
    <Diagrams></Diagrams>
  </Designer>
</edmx:Edmx>

---

Names & Namespaces :

Project Name : Business.Matches
Default Namespace : Xz.Business.Matches

I added an Entity Model with this definitions :

Model : RecordzModel

Context : RecordzContext

Model Namespace : Xz.Business.Matches

Answer 1

You seem to have more than one class in your project that is called ‘TblRecord’. Namespaces are ignored when matching your types to EDM types for POCO types and therefore if you have more than one class with the same name it is ambiguous and causes the exception.