Attribute for configuring DeleteBehavior

src/EFCore/DeleteBehavior.cs → src/EFCore.Abstractions/DeleteBehavior.cs

@@ -10,12 +10,15 @@ namespace Microsoft.EntityFrameworkCore;
 /// <remarks>
 ///     <para>
 ///         Behaviors in the database are dependent on the database schema being created
-///         appropriately. Using Entity Framework Migrations or <see cref="DatabaseFacade.EnsureCreated" />
+///         appropriately. Using Entity Framework Migrations or
+///         <see href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.infrastructure.databasefacade.ensurecreated">
+///         EnsureCreated()</see>
 ///         will create the appropriate schema.
 ///     </para>
 ///     <para>
 ///         Note that the in-memory behavior for entities that are currently tracked by
-///         the <see cref="DbContext" /> can be different from the behavior that happens in the database.
+///         the <see href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.dbcontext">DbContext</see>
+///         can be different from the behavior that happens in the database.
 ///     </para>
 ///     <para>
 ///         See <see href="https://aka.ms/efcore-docs-cascading">Cascade delete and deleting orphans in EF Core</see> for more information and
@@ -25,16 +28,20 @@ namespace Microsoft.EntityFrameworkCore;
 public enum DeleteBehavior
 {
     /// <summary>
-    ///     For entities being tracked by the <see cref="DbContext" />, the values of foreign key properties in
+    ///     For entities being tracked by the <see href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.dbcontext">
+    ///     DbContext</see>, the values of foreign key properties in
     ///     dependent entities are set to null when the related principal is deleted.
     ///     This helps keep the graph of entities in a consistent state while they are being tracked, such that a
     ///     fully consistent graph can then be written to the database. If a property cannot be set to null because
-    ///     it is not a nullable type, then an exception will be thrown when <see cref="DbContext.SaveChanges()" /> is called.
+    ///     it is not a nullable type, then an exception will be thrown when
+    ///     <see href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.dbcontext.savechanges?view=efcore-6.0#microsoft-entityframeworkcore-dbcontext-savechanges" >
+    ///     SaveChanges()</see> is called.
     /// </summary>
     /// <remarks>
     ///     <para>
     ///         If the database has been created from the model using Entity Framework Migrations or the
-    ///         <see cref="DatabaseFacade.EnsureCreated" /> method, then the behavior in the database
+    ///         <see href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.infrastructure.databasefacade.ensurecreated">
+    ///         EnsureCreated()</see> method, then the behavior in the database
     ///         is to generate an error if a foreign key constraint is violated.
     ///     </para>
     ///     <para>
@@ -45,29 +52,35 @@ public enum DeleteBehavior
     ClientSetNull,
 
     /// <summary>
-    ///     For entities being tracked by the <see cref="DbContext" />, the values of foreign key properties in
-    ///     dependent entities are set to null when the related principal is deleted.
+    ///     For entities being tracked by the <see href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.dbcontext">
+    ///     DbContext</see>, the values of foreign key properties in dependent entities are set to null when the related principal is deleted.
     ///     This helps keep the graph of entities in a consistent state while they are being tracked, such that a
     ///     fully consistent graph can then be written to the database. If a property cannot be set to null because
-    ///     it is not a nullable type, then an exception will be thrown when <see cref="DbContext.SaveChanges()" /> is called.
+    ///     it is not a nullable type, then an exception will be thrown when
+    ///     <see href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.dbcontext.savechanges?view=efcore-6.0#microsoft-entityframeworkcore-dbcontext-savechanges" >
+    ///     SaveChanges()</see> is called.
     /// </summary>
     /// <remarks>
     ///     If the database has been created from the model using Entity Framework Migrations or the
-    ///     <see cref="DatabaseFacade.EnsureCreated" /> method, then the behavior in the database
-    ///     is to generate an error if a foreign key constraint is violated.
+    ///     <see href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.infrastructure.databasefacade.ensurecreated">
+    ///     EnsureCreated()</see> method, then the behavior in the database is to generate an error if a foreign key constraint is violated.
     /// </remarks>
     Restrict,
 
     /// <summary>
-    ///     For entities being tracked by the <see cref="DbContext" />, the values of foreign key properties in
+    ///     For entities being tracked by the <see href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.dbcontext">
+    ///     DbContext</see>, the values of foreign key properties in
     ///     dependent entities are set to null when the related principal is deleted.
     ///     This helps keep the graph of entities in a consistent state while they are being tracked, such that a
     ///     fully consistent graph can then be written to the database. If a property cannot be set to null because
-    ///     it is not a nullable type, then an exception will be thrown when <see cref="DbContext.SaveChanges()" /> is called.
+    ///     it is not a nullable type, then an exception will be thrown when
+    ///     <see href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.dbcontext.savechanges?view=efcore-6.0#microsoft-entityframeworkcore-dbcontext-savechanges" >
+    ///     SaveChanges()</see> is called.
     /// </summary>
     /// <remarks>
     ///     If the database has been created from the model using Entity Framework Migrations or the
-    ///     <see cref="DatabaseFacade.EnsureCreated" /> method, then the behavior in the database is
+    ///     <see href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.infrastructure.databasefacade.ensurecreated">
+    ///     EnsureCreated()</see> method, then the behavior in the database is
     ///     the same as is described above for tracked entities. Keep in mind that some databases cannot easily
     ///     support this behavior, especially if there are cycles in relationships, in which case it may
     ///     be better to use <see cref="ClientSetNull" /> which will allow EF to cascade null values
@@ -76,13 +89,15 @@ public enum DeleteBehavior
     SetNull,
 
     /// <summary>
-    ///     For entities being tracked by the <see cref="DbContext" />, dependent entities
+    ///     For entities being tracked by the <see href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.dbcontext">
+    ///     DbContext</see>, dependent entities
     ///     will be deleted when the related principal is deleted.
     /// </summary>
     /// <remarks>
     ///     <para>
     ///         If the database has been created from the model using Entity Framework Migrations or the
-    ///         <see cref="DatabaseFacade.EnsureCreated" /> method, then the behavior in the database is
+    ///         <see href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.infrastructure.databasefacade.ensurecreated">
+    ///         EnsureCreated()</see> method, then the behavior in the database is
     ///         the same as is described above for tracked entities. Keep in mind that some databases cannot easily
     ///         support this behavior, especially if there are cycles in relationships, in which case it may
     ///         be better to use <see cref="ClientCascade" /> which will allow EF to perform cascade deletes
@@ -96,27 +111,30 @@ public enum DeleteBehavior
     Cascade,
 
     /// <summary>
-    ///     For entities being tracked by the <see cref="DbContext" />, dependent entities
+    ///     For entities being tracked by the <see href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.dbcontext">
+    ///     DbContext</see>, dependent entities
     ///     will be deleted when the related principal is deleted.
     /// </summary>
     /// <remarks>
     ///     If the database has been created from the model using Entity Framework Migrations or the
-    ///     <see cref="DatabaseFacade.EnsureCreated" /> method, then the behavior in the database
-    ///     is to generate an error if a foreign key constraint is violated.
+    ///     <see href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.infrastructure.databasefacade.ensurecreated">
+    ///     EnsureCreated()</see> method, then the behavior in the database is to generate an error if a foreign key constraint is violated.
     /// </remarks>
     ClientCascade,
 
     /// <summary>
-    ///     For entities being tracked by the <see cref="DbContext" />, the values of foreign key properties in
-    ///     dependent entities are set to null when the related principal is deleted.
+    ///     For entities being tracked by the <see href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.dbcontext">
+    ///     DbContext</see>, the values of foreign key properties in dependent entities are set to null when the related principal is deleted.
     ///     This helps keep the graph of entities in a consistent state while they are being tracked, such that a
     ///     fully consistent graph can then be written to the database. If a property cannot be set to null because
-    ///     it is not a nullable type, then an exception will be thrown when <see cref="DbContext.SaveChanges()" /> is called.
+    ///     it is not a nullable type, then an exception will be thrown when
+    ///     <see href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.dbcontext.savechanges?view=efcore-6.0#microsoft-entityframeworkcore-dbcontext-savechanges" >
+    ///     SaveChanges()</see> is called.
     /// </summary>
     /// <remarks>
     ///     If the database has been created from the model using Entity Framework Migrations or the
-    ///     <see cref="DatabaseFacade.EnsureCreated" /> method, then the behavior in the database
-    ///     is to generate an error if a foreign key constraint is violated.
+    ///     <see href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.infrastructure.databasefacade.ensurecreated">
+    ///     EnsureCreated()</see> method, then the behavior in the database is to generate an error if a foreign key constraint is violated.
     /// </remarks>
     NoAction,
 
@@ -126,15 +144,15 @@ public enum DeleteBehavior
     /// </summary>
     /// <remarks>
     ///     <para>
-    ///         For entities being tracked by the <see cref="DbContext" />, the values of foreign key properties in
-    ///         dependent entities are not changed when the related principal entity is deleted.
+    ///         For entities being tracked by the <see href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.dbcontext">
+    ///         DbContext</see>, the values of foreign key properties in dependent entities are not changed when the related principal entity is deleted.
     ///         This can result in an inconsistent graph of entities where the values of foreign key properties do
     ///         not match the relationships in the graph.
     ///     </para>
     ///     <para>
     ///         If the database has been created from the model using Entity Framework Migrations or the
-    ///         <see cref="DatabaseFacade.EnsureCreated" /> method, then the behavior in the database
-    ///         is to generate an error if a foreign key constraint is violated.
+    ///         <see href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.infrastructure.databasefacade.ensurecreated">
+    ///         EnsureCreated()</see> method, then the behavior in the database is to generate an error if a foreign key constraint is violated.
     ///     </para>
     /// </remarks>
     ClientNoAction

src/EFCore.Abstractions/DeleteBehaviorAttribute.cs

@@ -0,0 +1,29 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.EntityFrameworkCore;
+
+/// <summary>
+///     Configures the Property or Field to indicate how a delete operation is applied to dependent entities
+///     in a relationship when it is deleted or the relationship is severed.
+/// </summary>
+/// <remarks>
+///     See <see href="https://aka.ms/efcore-docs-modeling">Modeling entity types and relationships</see> for more information and examples.
+/// </remarks>
+[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field)]
+public sealed class DeleteBehaviorAttribute : Attribute
+{
+    /// <summary>
+    ///     Initializes a new instance of the <see cref="DeleteBehaviorAttribute" /> class.
+    /// </summary>
+    /// <param name="behavior">The DeleteBehavior value of entity</param>
+    public DeleteBehaviorAttribute(DeleteBehavior behavior)
+    {
+        Behavior = behavior;
+    }
+
+    /// <summary>
+    ///     The DeleteBehavior value
+    /// </summary>
+    public DeleteBehavior Behavior { get; }
+}

src/EFCore/Metadata/Conventions/DeleteBehaviorAttributeConvention.cs

@@ -0,0 +1,46 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.EntityFrameworkCore.Metadata.Conventions;
+
+/// <summary>
+///     A convention that configures the DeleteBehavior based on the <see cref="DeleteBehaviorAttribute" /> applied on the property.
+/// </summary>
+/// <remarks>
+///     See <see href="https://aka.ms/efcore-docs-conventions">Model building conventions</see> for more information and examples.
+/// </remarks>
+public class DeleteBehaviorAttributeConvention : IForeignKeyAddedConvention
+{
+    /// <summary>
+    ///     Creates a new instance of <see cref="UnicodeAttributeConvention" />.
+    /// </summary>
+    /// <param name="dependencies">Parameter object containing dependencies for this convention.</param>
+    public DeleteBehaviorAttributeConvention(ProviderConventionSetBuilderDependencies dependencies)
+    {
+        Dependencies = dependencies;
+    }
+
+    /// <summary>
+    ///     Dependencies for this service.
+    /// </summary>
+    protected virtual ProviderConventionSetBuilderDependencies Dependencies { get; }
+
+    /// <summary>
+    ///     Called after a foreign key is added to the entity type.
+    /// </summary>
+    /// <param name="foreignKeyBuilder">The builder for the foreign key.</param>
+    /// <param name="context">Additional information associated with convention execution.</param>
+    public virtual void ProcessForeignKeyAdded(IConventionForeignKeyBuilder foreignKeyBuilder, IConventionContext<IConventionForeignKeyBuilder> context)
+    {
+        var foreignKey = foreignKeyBuilder.Metadata;
+        var properties = foreignKey.Properties;
+        foreach (var property in properties)
+        {
+            var attribute = property?.PropertyInfo?.GetCustomAttribute<DeleteBehaviorAttribute>();
+            if (attribute != null)
+            {
+                foreignKey.SetDeleteBehavior(attribute.Behavior);
+            }
+        }
+    }
+}

src/EFCore/Metadata/Conventions/Infrastructure/ProviderConventionSetBuilder.cs

@@ -141,13 +141,15 @@ public virtual ConventionSet CreateConventionSet()
         conventionSet.KeyRemovedConventions.Add(keyDiscoveryConvention);
 
         var cascadeDeleteConvention = new CascadeDeleteConvention(Dependencies);
+        var deleteBehaviorAttributeConvention = new DeleteBehaviorAttributeConvention(Dependencies);
 
         conventionSet.ForeignKeyAddedConventions.Add(foreignKeyAttributeConvention);
         conventionSet.ForeignKeyAddedConventions.Add(foreignKeyPropertyDiscoveryConvention);
         conventionSet.ForeignKeyAddedConventions.Add(keyDiscoveryConvention);
         conventionSet.ForeignKeyAddedConventions.Add(valueGeneratorConvention);
         conventionSet.ForeignKeyAddedConventions.Add(cascadeDeleteConvention);
         conventionSet.ForeignKeyAddedConventions.Add(foreignKeyIndexConvention);
+        conventionSet.ForeignKeyAddedConventions.Add(deleteBehaviorAttributeConvention);
 
         conventionSet.ForeignKeyRemovedConventions.Add(baseTypeDiscoveryConvention);
         conventionSet.ForeignKeyRemovedConventions.Add(relationshipDiscoveryConvention);

src/EFCore/Properties/TypeForwards.cs

@@ -8,3 +8,4 @@
 [assembly: TypeForwardedTo(typeof(ObservableCollectionExtensions))]
 [assembly: TypeForwardedTo(typeof(ObservableCollectionListSource<>))]
 [assembly: TypeForwardedTo(typeof(SortableBindingList<>))]
+[assembly: TypeForwardedTo(typeof(DeleteBehavior))]

test/EFCore.Design.Tests/Migrations/ModelSnapshotSqlServerTest.cs

@@ -6083,6 +6083,7 @@ protected virtual ICollection<BuildReference> GetReferences()
         => new List<BuildReference>
         {
             BuildReference.ByName("Microsoft.EntityFrameworkCore"),
+            BuildReference.ByName("Microsoft.EntityFrameworkCore.Abstractions"),
             BuildReference.ByName("Microsoft.EntityFrameworkCore.Relational"),
             BuildReference.ByName("Microsoft.EntityFrameworkCore.SqlServer"),
             BuildReference.ByName("NetTopologySuite")

test/EFCore.Relational.Specification.Tests/Migrations/MigrationsTestBase.cs

@@ -2023,6 +2023,7 @@ protected IModel BuildModelFromSnapshotSource(string code)
 
         // Add standard EF references, a reference to the provider's assembly, and any extra references added by the provider's test suite
         build.References.Add(BuildReference.ByName("Microsoft.EntityFrameworkCore"));
+        build.References.Add(BuildReference.ByName("Microsoft.EntityFrameworkCore.Abstractions"));
         build.References.Add(BuildReference.ByName("Microsoft.EntityFrameworkCore.Relational"));
 
         var databaseProvider = Fixture.TestHelpers.CreateContextServices().GetRequiredService<IDatabaseProvider>();