OK, this problem has it all.
Conceptually, I have a Resource object that can have many resources for children and many parent resources. The resource table has two fields: an identifier and a name with an identifier that is the primary key.
To complete the many-many relationship, I created a ResourceHierarchy table that has two fields: (Parent_ID, Child_ID) and two foreign keys, each of which refers to the primary key of the resource table (ID), and the ResourceHierarchy table has a composite primary key ( Parent_ID, Child_ID)
Now we already know that each resource can act as a parent or child on other resources, but logically not all resources will have a parent element, but also. As an example, I can say that in my resource table there are the following resources.
ID Name
10000 Little House
10001 Font Door
10002 Roof
10003 Roof Tile
10004 Tile Monster
And in the ResourceHierarchy table, we have the following relationships.
Parent_ID Child_ID
10000 10001
10000 10002
10002 10003
10004 10003
Then the Entity Framework generates Entity, so good ...
If you checked the generated code in the edmx file, you will see that the ResourceHierarchy table is treated as a relation, and the ResourceHierarchy table is not available through the code because it is not considered as an entity.
If that’s all I wanted, it would work out fine.
, Resource. , , .
, Resource, .
ID Name Quantity
10000 Little House 1
10001 Font Door 1
10002 Roof 1
10003 Roof Tile 5
10004 Tile Monster 1
, 5 . , , ResourceHierarchy, , , , ResourceHierarchy , , . , , "/", . , Entity , Resource, , Resource.Children.Add(r) ResourceHierarchy db, , , .. , , .
ResourceHierarchy "", .
Parent_ID Child_ID Quantity
10000 10001 1
10000 10002 1
10002 10003 8
10004 10003 13
"", "" - "" .
, , ResourceHierarchy, , , .
!
edmx ResourceHierarchy db.
, - Resource is ResourceType, ResourceHierarchy - ResourceTypeHierarchy.
SSDL , EntityType ResourceTypeHierarchy, .
-
<edmx:ConceptualModels>
<Schema Namespace="MyModel" Alias="Self" xmlns:store="http://schemas.microsoft.com/ado/2007/12/edm/EntityStoreSchemaGenerator" xmlns="http://schemas.microsoft.com/ado/2008/09/edm">
<EntityContainer Name="MyEntities">
<EntitySet Name="ResourceTypes" EntityType="MyModel.ResourceType" />
<AssociationSet Name="ResourceTypeHierarchy" Association="MyModel.ResourceTypeHierarchy">
<End Role="ResourceType" EntitySet="ResourceTypes" />
<End Role="ResourceType1" EntitySet="ResourceTypes" /></AssociationSet></EntityContainer>
<EntityType Name="ResourceType">
<Key>
<PropertyRef Name="ID" /></Key>
<Property Type="Int32" Name="ID" Nullable="false" />
<Property Type="String" Name="Type" Nullable="false" MaxLength="25" FixedLength="false" Unicode="false" />
<NavigationProperty Name="Parents" Relationship="MyModel.ResourceTypeHierarchy" FromRole="ResourceType" ToRole="ResourceType1" />
<NavigationProperty Name="Children" Relationship="MyModel.ResourceTypeHierarchy" FromRole="ResourceType1" ToRole="ResourceType" /></EntityType>
<Association Name="ResourceTypeHierarchy">
<End Type="MyModel.ResourceType" Role="ResourceType" Multiplicity="*" />
<End Type="MyModel.ResourceType" Role="ResourceType1" Multiplicity="*" /></Association></Schema>
</edmx:ConceptualModels>
<edmx:Mappings>
<Mapping Space="C-S" xmlns="http://schemas.microsoft.com/ado/2008/09/mapping/cs">
<EntityContainerMapping StorageEntityContainer="MyModelStoreContainer" CdmEntityContainer="MyEntities">
<EntitySetMapping Name="ResourceTypes">
<EntityTypeMapping TypeName="IsTypeOf(MyModel.ResourceType)">
<MappingFragment StoreEntitySet="ResourceType">
<ScalarProperty Name="ID" ColumnName="ID" />
<ScalarProperty Name="Type" ColumnName="Type" /></MappingFragment></EntityTypeMapping></EntitySetMapping>
<AssociationSetMapping Name="ResourceTypeHierarchy" TypeName="MyModel.ResourceTypeHierarchy" StoreEntitySet="ResourceTypeHierarchy">
<EndProperty Name="ResourceType1">
<ScalarProperty Name="ID" ColumnName="Parent_ID" /></EndProperty>
<EndProperty Name="ResourceType">
<ScalarProperty Name="ID" ColumnName="Child_ID" /></EndProperty></AssociationSetMapping></EntityContainerMapping>
</Mapping>
</edmx:Mappings>
<edmx:Mappings>
<Mapping Space="C-S" xmlns="http://schemas.microsoft.com/ado/2008/09/mapping/cs">
<EntityContainerMapping StorageEntityContainer="MyModelStoreContainer" CdmEntityContainer="MyEntities">
<EntitySetMapping Name="ResourceTypes">
<EntityTypeMapping TypeName="IsTypeOf(MyModel.ResourceType)">
<MappingFragment StoreEntitySet="ResourceType">
<ScalarProperty Name="ID" ColumnName="ID" />
<ScalarProperty Name="Type" ColumnName="Type" /></MappingFragment></EntityTypeMapping></EntitySetMapping>
<EntitySetMapping Name="ResourceTypeHierarchies">
<EntityTypeMapping TypeName="IsTypeOf(MyModel.ResourceTypeHierarchy)">
<MappingFragment StoreEntitySet="ResourceTypeHierarchy">
<ScalarProperty Name="Child_ID" ColumnName="Child_ID" />
<ScalarProperty Name="Parent_ID" ColumnName="Parent_ID" />
<ScalarProperty Name="Quantity" ColumnName="Quantity" /></MappingFragment></EntityTypeMapping></EntitySetMapping>
<AssociationSetMapping Name="FK_Child" TypeName="MyModel.FK_Child" StoreEntitySet="ResourceTypeHierarchy">
<EndProperty Name="ResourceTypeHierarchy">
<ScalarProperty Name="Child_ID" ColumnName="Child_ID" />
<ScalarProperty Name="Parent_ID" ColumnName="Parent_ID" /></EndProperty>
<EndProperty Name="ResourceType">
<ScalarProperty Name="ID" ColumnName="Child_ID" /></EndProperty></AssociationSetMapping>
<AssociationSetMapping Name="FK_Parent" TypeName="MyModel.FK_Parent" StoreEntitySet="ResourceTypeHierarchy">
<EndProperty Name="ResourceTypeHierarchy">
<ScalarProperty Name="Child_ID" ColumnName="Child_ID" />
<ScalarProperty Name="Parent_ID" ColumnName="Parent_ID" /></EndProperty>
<EndProperty Name="ResourceType">
<ScalarProperty Name="ID" ColumnName="Parent_ID" /></EndProperty></AssociationSetMapping></EntityContainerMapping>
</Mapping>
</edmx:Mappings>