My relationship between parent and child is such that they are connected by a rib. This is similar to the structure of a directed graph.
DAL:
public void SaveResource(Resource resource)
{
context.AddToResources(resource);
context.SaveChanges();
}
public Resource GetResource(int resourceId)
{
var resource = (from r in context.Resources
.Include("ToEdges").Include("FromEdges")
where r.ResourceId == resourceId
select r).SingleOrDefault();
return resource;
}
Service:
public void AddChildResource(int parentResourceId, Resource childResource)
{
Resource parentResource = repository.GetResource(parentResourceId);
ResourceEdge inEdge = new ResourceEdge();
inEdge.ToResource = childResource;
parentResource.ToEdges.Add(inEdge);
repository.SaveResource(parentResource);
}
Error: An object with the same key already exists in ObjectStateManager. An existing object is in an unchanged state. An object can be added to the ObjectStateManager again only if it is in the added state.
Form:
I was told that this is the sequence of sending a child to an existing parent:
Get parent → Attach child to parent → send parent.
This is the sequence I used. The above code is retrieved from an ASP.NET MVC 2 application using a repository template.
EDMX file:
<?xml version="1.0" encoding="utf-8"?>
<edmx:Edmx Version="2.0" xmlns:edmx="http://schemas.microsoft.com/ado/2008/10/edmx">
<edmx:Runtime>
<edmx:StorageModels>
<Schema Namespace="XDbModel.Store" Alias="Self" Provider="System.Data.SqlClient" ProviderManifestToken="2008" xmlns:store="http://schemas.microsoft.com/ado/2007/12/edm/EntityStoreSchemaGenerator" xmlns="http://schemas.microsoft.com/ado/2009/02/edm/ssdl">
<EntityContainer Name="XDbModelStoreContainer">
<EntitySet Name="Bundles" EntityType="XDbModel.Store.Bundles" store:Type="Tables" Schema="dbo" />
<EntitySet Name="CellProviders" EntityType="XDbModel.Store.CellProviders" store:Type="Tables" Schema="dbo" />
<EntitySet Name="Comments" EntityType="XDbModel.Store.Comments" store:Type="Tables" Schema="dbo" />
<EntitySet Name="LocationPoints" EntityType="XDbModel.Store.LocationPoints" store:Type="Tables" Schema="dbo" />
<EntitySet Name="Locations" EntityType="XDbModel.Store.Locations" store:Type="Tables" Schema="dbo" />
<EntitySet Name="Offers" EntityType="XDbModel.Store.Offers" store:Type="Tables" Schema="dbo" />
<EntitySet Name="PostBundleJunction" EntityType="XDbModel.Store.PostBundleJunction" store:Type="Tables" Schema="dbo" />
<EntitySet Name="PostMedia" EntityType="XDbModel.Store.PostMedia" store:Type="Tables" Schema="dbo" />
<EntitySet Name="Posts" EntityType="XDbModel.Store.Posts" store:Type="Tables" Schema="dbo" />
<EntitySet Name="ResourceEdges" EntityType="XDbModel.Store.ResourceEdges" store:Type="Tables" Schema="dbo" />
<EntitySet Name="ResourceNames" EntityType="XDbModel.Store.ResourceNames" store:Type="Tables" Schema="dbo" />
<EntitySet Name="Resources" EntityType="XDbModel.Store.Resources" store:Type="Tables" Schema="dbo" />
<EntitySet Name="sysdiagrams" EntityType="XDbModel.Store.sysdiagrams" store:Type="Tables" Schema="dbo" />
<EntitySet Name="Users" EntityType="XDbModel.Store.Users" store:Type="Tables" Schema="dbo" />
<EntitySet Name="Votes" EntityType="XDbModel.Store.Votes" store:Type="Tables" Schema="dbo" />
<AssociationSet Name="FK_Comments_Offers" Association="XDbModel.Store.FK_Comments_Offers">
<End Role="Offers" EntitySet="Offers" />
<End Role="Comments" EntitySet="Comments" />
</AssociationSet>
<AssociationSet Name="FK_Comments_Users" Association="XDbModel.Store.FK_Comments_Users">
<End Role="Users" EntitySet="Users" />
<End Role="Comments" EntitySet="Comments" />
</AssociationSet>
<AssociationSet Name="FK_LocationPoints_Locations" Association="XDbModel.Store.FK_LocationPoints_Locations">
<End Role="Locations" EntitySet="Locations" />
<End Role="LocationPoints" EntitySet="LocationPoints" />
</AssociationSet>
<AssociationSet Name="FK_PostBundleJunction_Bundles" Association="XDbModel.Store.FK_PostBundleJunction_Bundles">
<End Role="Bundles" EntitySet="Bundles" />
<End Role="PostBundleJunction" EntitySet="PostBundleJunction" />
</AssociationSet>
<AssociationSet Name="FK_PostBundleJunction_Posts" Association="XDbModel.Store.FK_PostBundleJunction_Posts">
<End Role="Posts" EntitySet="Posts" />
<End Role="PostBundleJunction" EntitySet="PostBundleJunction" />
</AssociationSet>
<AssociationSet Name="FK_Posts_Locations" Association="XDbModel.Store.FK_Posts_Locations">
<End Role="Locations" EntitySet="Locations" />
<End Role="Posts" EntitySet="Posts" />
</AssociationSet>
<AssociationSet Name="FK_Posts_ResourceNames" Association="XDbModel.Store.FK_Posts_ResourceNames">
<End Role="ResourceNames" EntitySet="ResourceNames" />
<End Role="Posts" EntitySet="Posts" />
</AssociationSet>
<AssociationSet Name="FK_Posts_Users" Association="XDbModel.Store.FK_Posts_Users">
<End Role="Users" EntitySet="Users" />
<End Role="Posts" EntitySet="Posts" />
</AssociationSet>
<AssociationSet Name="FK_ResourceEdges_Resources" Association="XDbModel.Store.FK_ResourceEdges_Resources">
<End Role="Resources" EntitySet="Resources" />
<End Role="ResourceEdges" EntitySet="ResourceEdges" />
</AssociationSet>
<AssociationSet Name="FK_ResourceEdges_Resources1" Association="XDbModel.Store.FK_ResourceEdges_Resources1">
<End Role="Resources" EntitySet="Resources" />
<End Role="ResourceEdges" EntitySet="ResourceEdges" />
</AssociationSet>
<AssociationSet Name="FK_ResourceNames_Resources" Association="XDbModel.Store.FK_ResourceNames_Resources">
<End Role="Resources" EntitySet="Resources" />
<End Role="ResourceNames" EntitySet="ResourceNames" />
</AssociationSet>
<AssociationSet Name="FK_Users_Locations" Association="XDbModel.Store.FK_Users_Locations">
<End Role="Locations" EntitySet="Locations" />
<End Role="Users" EntitySet="Users" />
</AssociationSet>
<AssociationSet Name="FK_Votes_Posts" Association="XDbModel.Store.FK_Votes_Posts">
<End Role="Posts" EntitySet="Posts" />
<End Role="Votes" EntitySet="Votes" />
</AssociationSet>
</EntityContainer>
<EntityType Name="Bundles">
<Key>
<PropertyRef Name="BundleId" />
</Key>
<Property Name="BundleId" Type="int" Nullable="false" />
</EntityType>
<EntityType Name="CellProviders">
<Key>
<PropertyRef Name="CellProviderID" />
</Key>
<Property Name="CellProviderID" Type="uniqueidentifier" Nullable="false" />
</EntityType>
<EntityType Name="Comments">
<Key>
<PropertyRef Name="CommentID" />
</Key>
<Property Name="CommentID" Type="uniqueidentifier" Nullable="false" />
<Property Name="ParentPostID" Type="uniqueidentifier" />
<Property Name="OfferPostID" Type="uniqueidentifier" />
<Property Name="UserID" Type="uniqueidentifier" Nullable="false" />
</EntityType>
<EntityType Name="LocationPoints">
<Key>
<PropertyRef Name="LocationPointId" />
</Key>
<Property Name="LocationPointId" Type="int" Nullable="false" StoreGeneratedPattern="Identity" />
<Property Name="Latitude" Type="float" Nullable="false" />
<Property Name="Longitude" Type="float" Nullable="false" />
<Property Name="Altitude" Type="float" Nullable="false" />
<Property Name="Count" Type="int" Nullable="false" />
<Property Name="LocationId" Type="int" Nullable="false" />
</EntityType>
<EntityType Name="Locations">
<Key>
<PropertyRef Name="LocationId" />
</Key>
<Property Name="LocationId" Type="int" Nullable="false" StoreGeneratedPattern="Identity" />
<Property Name="Address1" Type="nvarchar" Nullable="false" MaxLength="200" />
<Property Name="Address2" Type="nvarchar" MaxLength="200" />
<Property Name="Address3" Type="nvarchar" MaxLength="200" />
<Property Name="State" Type="nvarchar" Nullable="false" MaxLength="200" />
<Property Name="Country" Type="nvarchar" Nullable="false" MaxLength="200" />
</EntityType>
<EntityType Name="Offers">
<Key>
<PropertyRef Name="OfferID" />
</Key>
<Property Name="OfferID" Type="uniqueidentifier" Nullable="false" />
<Property Name="NeedOffer" Type="uniqueidentifier" Nullable="false" />
<Property Name="ProvisionOffer" Type="uniqueidentifier" Nullable="false" />
</EntityType>
<EntityType Name="PostBundleJunction">
<Key>
<PropertyRef Name="BundleId" />
<PropertyRef Name="PostId" />
</Key>
<Property Name="BundleId" Type="int" Nullable="false" />
<Property Name="PostId" Type="int" Nullable="false" />
</EntityType>
<EntityType Name="PostMedia">
<Key>
<PropertyRef Name="MediaId" />
</Key>
<Property Name="MediaId" Type="int" Nullable="false" StoreGeneratedPattern="Identity" />
<Property Name="MediaExt" Type="nvarchar" Nullable="false" MaxLength="5" />
<Property Name="PostId" Type="int" Nullable="false" />
<Property Name="SynthId" Type="uniqueidentifier" />
</EntityType>
<EntityType Name="Posts">
<Key>
<PropertyRef Name="PostId" />
</Key>
<Property Name="PostId" Type="int" Nullable="false" StoreGeneratedPattern="Identity" />
<Property Name="PosterID" Type="uniqueidentifier" Nullable="false" />
<Property Name="BundleId" Type="int" Nullable="false" />
<Property Name="LocationId" Type="int" Nullable="false" />
<Property Name="Tags" Type="uniqueidentifier" />
<Property Name="Quanitity" Type="int" Nullable="false" />
<Property Name="Description" Type="text" Nullable="false" />
<Property Name="ResourceNameId" Type="int" Nullable="false" />
<Property Name="Date" Type="datetime" Nullable="false" />
</EntityType>
<EntityType Name="ResourceEdges">
<Key>
<PropertyRef Name="EdgeId" />
</Key>
<Property Name="Rank" Type="int" Nullable="false" />
<Property Name="EdgeId" Type="int" Nullable="false" StoreGeneratedPattern="Identity" />
<Property Name="ToResourceId" Type="int" Nullable="false" />
<Property Name="FromResourrceId" Type="int" Nullable="false" />
</EntityType>
<EntityType Name="ResourceNames">
<Key>
<PropertyRef Name="ResourceNameId" />
</Key>
<Property Name="ResourceNameId" Type="int" Nullable="false" StoreGeneratedPattern="Identity" />
<Property Name="Name" Type="nvarchar" Nullable="false" MaxLength="100" />
<Property Name="ResourceId" Type="int" Nullable="false" />
</EntityType>
<EntityType Name="Resources">
<Key>
<PropertyRef Name="ResourceId" />
</Key>
<Property Name="ResourceId" Type="int" Nullable="false" StoreGeneratedPattern="Identity" />
<Property Name="Description" Type="nvarchar" MaxLength="50" />
</EntityType>
<EntityType Name="sysdiagrams">
<Key>
<PropertyRef Name="diagram_id" />
</Key>
<Property Name="name" Type="nvarchar" Nullable="false" MaxLength="128" />
<Property Name="principal_id" Type="int" Nullable="false" />
<Property Name="diagram_id" Type="int" Nullable="false" StoreGeneratedPattern="Identity" />
<Property Name="version" Type="int" />
<Property Name="definition" Type="varbinary(max)" />
</EntityType>
<EntityType Name="Users">
<Key>
<PropertyRef Name="UserID" />
</Key>
<Property Name="UserID" Type="uniqueidentifier" Nullable="false" />
<Property Name="LocationId" Type="int" />
</EntityType>
<EntityType Name="Votes">
<Key>
<PropertyRef Name="VoteId" />
</Key>
<Property Name="VoteId" Type="int" Nullable="false" />
<Property Name="VoterId" Type="uniqueidentifier" Nullable="false" />
<Property Name="VoteContent" Type="int" Nullable="false" />
<Property Name="PostId" Type="int" Nullable="false" />
</EntityType>
<Association Name="FK_Comments_Offers">
<End Role="Offers" Type="XDbModel.Store.Offers" Multiplicity="0..1" />
<End Role="Comments" Type="XDbModel.Store.Comments" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Offers">
<PropertyRef Name="OfferID" />
</Principal>
<Dependent Role="Comments">
<PropertyRef Name="OfferPostID" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_Comments_Users">
<End Role="Users" Type="XDbModel.Store.Users" Multiplicity="1">
<OnDelete Action="Cascade" />
</End>
<End Role="Comments" Type="XDbModel.Store.Comments" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Users">
<PropertyRef Name="UserID" />
</Principal>
<Dependent Role="Comments">
<PropertyRef Name="UserID" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_LocationPoints_Locations">
<End Role="Locations" Type="XDbModel.Store.Locations" Multiplicity="1">
<OnDelete Action="Cascade" />
</End>
<End Role="LocationPoints" Type="XDbModel.Store.LocationPoints" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Locations">
<PropertyRef Name="LocationId" />
</Principal>
<Dependent Role="LocationPoints">
<PropertyRef Name="LocationId" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_PostBundleJunction_Bundles">
<End Role="Bundles" Type="XDbModel.Store.Bundles" Multiplicity="1" />
<End Role="PostBundleJunction" Type="XDbModel.Store.PostBundleJunction" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Bundles">
<PropertyRef Name="BundleId" />
</Principal>
<Dependent Role="PostBundleJunction">
<PropertyRef Name="BundleId" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_PostBundleJunction_Posts">
<End Role="Posts" Type="XDbModel.Store.Posts" Multiplicity="1" />
<End Role="PostBundleJunction" Type="XDbModel.Store.PostBundleJunction" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Posts">
<PropertyRef Name="PostId" />
</Principal>
<Dependent Role="PostBundleJunction">
<PropertyRef Name="PostId" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_Posts_Locations">
<End Role="Locations" Type="XDbModel.Store.Locations" Multiplicity="1" />
<End Role="Posts" Type="XDbModel.Store.Posts" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Locations">
<PropertyRef Name="LocationId" />
</Principal>
<Dependent Role="Posts">
<PropertyRef Name="LocationId" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_Posts_ResourceNames">
<End Role="ResourceNames" Type="XDbModel.Store.ResourceNames" Multiplicity="1" />
<End Role="Posts" Type="XDbModel.Store.Posts" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="ResourceNames">
<PropertyRef Name="ResourceNameId" />
</Principal>
<Dependent Role="Posts">
<PropertyRef Name="ResourceNameId" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_Posts_Users">
<End Role="Users" Type="XDbModel.Store.Users" Multiplicity="1" />
<End Role="Posts" Type="XDbModel.Store.Posts" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Users">
<PropertyRef Name="UserID" />
</Principal>
<Dependent Role="Posts">
<PropertyRef Name="PosterID" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_ResourceEdges_Resources">
<End Role="Resources" Type="XDbModel.Store.Resources" Multiplicity="1" />
<End Role="ResourceEdges" Type="XDbModel.Store.ResourceEdges" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Resources">
<PropertyRef Name="ResourceId" />
</Principal>
<Dependent Role="ResourceEdges">
<PropertyRef Name="ToResourceId" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_ResourceEdges_Resources1">
<End Role="Resources" Type="XDbModel.Store.Resources" Multiplicity="1" />
<End Role="ResourceEdges" Type="XDbModel.Store.ResourceEdges" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Resources">
<PropertyRef Name="ResourceId" />
</Principal>
<Dependent Role="ResourceEdges">
<PropertyRef Name="FromResourrceId" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_ResourceNames_Resources">
<End Role="Resources" Type="XDbModel.Store.Resources" Multiplicity="1">
<OnDelete Action="Cascade" />
</End>
<End Role="ResourceNames" Type="XDbModel.Store.ResourceNames" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Resources">
<PropertyRef Name="ResourceId" />
</Principal>
<Dependent Role="ResourceNames">
<PropertyRef Name="ResourceId" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_Users_Locations">
<End Role="Locations" Type="XDbModel.Store.Locations" Multiplicity="0..1">
<OnDelete Action="Cascade" />
</End>
<End Role="Users" Type="XDbModel.Store.Users" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Locations">
<PropertyRef Name="LocationId" />
</Principal>
<Dependent Role="Users">
<PropertyRef Name="LocationId" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_Votes_Posts">
<End Role="Posts" Type="XDbModel.Store.Posts" Multiplicity="1">
<OnDelete Action="Cascade" />
</End>
<End Role="Votes" Type="XDbModel.Store.Votes" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Posts">
<PropertyRef Name="PostId" />
</Principal>
<Dependent Role="Votes">
<PropertyRef Name="PostId" />
</Dependent>
</ReferentialConstraint>
</Association>
</Schema>
</edmx:StorageModels>
<edmx:ConceptualModels>
<Schema Namespace="XDbModel" Alias="Self" xmlns:annotation="http://schemas.microsoft.com/ado/2009/02/edm/annotation" xmlns="http://schemas.microsoft.com/ado/2008/09/edm">
<EntityContainer Name="XDbEntities" annotation:LazyLoadingEnabled="true">
<EntitySet Name="Bundles" EntityType="XDbModel.Bundle" />
<EntitySet Name="CellProviders" EntityType="XDbModel.CellProvider" />
<EntitySet Name="Comments" EntityType="XDbModel.Comment" />
<EntitySet Name="LocationPoints" EntityType="XDbModel.LocationPoint" />
<EntitySet Name="Locations" EntityType="XDbModel.Location" />
<EntitySet Name="Offers" EntityType="XDbModel.Offer" />
<EntitySet Name="PostMedias" EntityType="XDbModel.PostMedia" />
<EntitySet Name="Posts" EntityType="XDbModel.Post" />
<EntitySet Name="ResourceEdges" EntityType="XDbModel.ResourceEdge" />
<EntitySet Name="ResourceNames" EntityType="XDbModel.ResourceName" />
<EntitySet Name="Resources" EntityType="XDbModel.Resource" />
<EntitySet Name="sysdiagrams" EntityType="XDbModel.sysdiagram" />
<EntitySet Name="Users" EntityType="XDbModel.User" />
<EntitySet Name="Votes" EntityType="XDbModel.Vote" />
<AssociationSet Name="FK_Comments_Offers" Association="XDbModel.FK_Comments_Offers">
<End Role="Offers" EntitySet="Offers" />
<End Role="Comments" EntitySet="Comments" />
</AssociationSet>
<AssociationSet Name="FK_Comments_Users" Association="XDbModel.FK_Comments_Users">
<End Role="Users" EntitySet="Users" />
<End Role="Comments" EntitySet="Comments" />
</AssociationSet>
<AssociationSet Name="FK_LocationPoints_Locations" Association="XDbModel.FK_LocationPoints_Locations">
<End Role="Locations" EntitySet="Locations" />
<End Role="LocationPoints" EntitySet="LocationPoints" />
</AssociationSet>
<AssociationSet Name="FK_Posts_Locations" Association="XDbModel.FK_Posts_Locations">
<End Role="Locations" EntitySet="Locations" />
<End Role="Posts" EntitySet="Posts" />
</AssociationSet>
<AssociationSet Name="FK_Users_Locations" Association="XDbModel.FK_Users_Locations">
<End Role="Locations" EntitySet="Locations" />
<End Role="Users" EntitySet="Users" />
</AssociationSet>
<AssociationSet Name="FK_Posts_ResourceNames" Association="XDbModel.FK_Posts_ResourceNames">
<End Role="ResourceNames" EntitySet="ResourceNames" />
<End Role="Posts" EntitySet="Posts" />
</AssociationSet>
<AssociationSet Name="FK_Posts_Users" Association="XDbModel.FK_Posts_Users">
<End Role="Users" EntitySet="Users" />
<End Role="Posts" EntitySet="Posts" />
</AssociationSet>
<AssociationSet Name="FK_Votes_Posts" Association="XDbModel.FK_Votes_Posts">
<End Role="Posts" EntitySet="Posts" />
<End Role="Votes" EntitySet="Votes" />
</AssociationSet>
<AssociationSet Name="FK_ResourceEdges_Resources" Association="XDbModel.FK_ResourceEdges_Resources">
<End Role="Resources" EntitySet="Resources" />
<End Role="ResourceEdges" EntitySet="ResourceEdges" />
</AssociationSet>
<AssociationSet Name="FK_ResourceEdges_Resources1" Association="XDbModel.FK_ResourceEdges_Resources1">
<End Role="Resources" EntitySet="Resources" />
<End Role="ResourceEdges" EntitySet="ResourceEdges" />
</AssociationSet>
<AssociationSet Name="FK_ResourceNames_Resources" Association="XDbModel.FK_ResourceNames_Resources">
<End Role="Resources" EntitySet="Resources" />
<End Role="ResourceNames" EntitySet="ResourceNames" />
</AssociationSet>
<AssociationSet Name="PostBundleJunction" Association="XDbModel.PostBundleJunction">
<End Role="Bundles" EntitySet="Bundles" />
<End Role="Posts" EntitySet="Posts" />
</AssociationSet>
</EntityContainer>
<EntityType Name="Bundle">
<Key>
<PropertyRef Name="BundleId" />
</Key>
<Property Name="BundleId" Type="Int32" Nullable="false" />
<NavigationProperty Name="Posts" Relationship="XDbModel.PostBundleJunction" FromRole="Bundles" ToRole="Posts" />
</EntityType>
<EntityType Name="CellProvider">
<Key>
<PropertyRef Name="CellProviderID" />
</Key>
<Property Name="CellProviderID" Type="Guid" Nullable="false" />
</EntityType>
<EntityType Name="Comment">
<Key>
<PropertyRef Name="CommentID" />