For NH-1262: Ported cascade delete orphans functionality for one-to-one mappings from Hibernate to NHibernate.

Mappings can be made in XML or MappingByCode.

The following scenarios are supported:

1) Bidirectional primary key based one-to-one.
2) Unidirectional shared primary key based one-to-one
3) Bidirectional foreign key based one-to-one with orphan delete declared on the non-constrained (<one-to-one/>) side.
4) Bidirectional foreign key based one-to-one with orphan delete declared on the constrained (<many-to-one unique="true"/>) side.
5) Unidirectional foreign key based one-to-one with orphan delete declared on the constrained (<many-to-one unique="true"/>) side.
6) Unidirectional foreign key based one-to-one with orphan delete declared on the constrained side (<many-to-one unique="true"/>) where the foreign key is composite (multiple columns).

Author: mickfold

doc/reference/modules/basic_mapping.xml

@@ -1628,7 +1628,7 @@
         name="PropertyName"
         column="column_name"
         class="ClassName"
-        cascade="all|none|save-update|delete"
+        cascade="all|none|save-update|delete|delete-orphan|all-delete-orphan"
         fetch="join|select"
         update="true|false"
         insert="true|false"
@@ -1788,7 +1788,7 @@
                 <programlisting><![CDATA[<one-to-one
         name="PropertyName"
         class="ClassName"
-        cascade="all|none|save-update|delete"
+        cascade="all|none|save-update|delete|delete-orphan|all-delete-orphan"
         constrained="true|false"
         fetch="join|select"
         property-ref="PropertyNameFromAssociatedClass"

doc/reference/modules/manipulating_data.xml

@@ -1043,14 +1043,15 @@ finally
         </itemizedlist>
 
         <para>
-            Mapping an association (many-to-one, or collection) with <literal>cascade="all"</literal>
+            Mapping an association (many-to-one, one-to-one or collection) with <literal>cascade="all"</literal>
             marks the association as a <emphasis>parent/child</emphasis> style relationship where
             save/update/deletion of the parent results in save/update/deletion of the child(ren).
             Futhermore, a mere reference to a child from a persistent parent will result in save / update
             of the child. The metaphor is incomplete, however. A child which becomes unreferenced by its
-            parent is <emphasis>not</emphasis> automatically deleted, except in the case of a
-            <literal>&lt;one-to-many&gt;</literal> association mapped with
-            <literal>cascade="all-delete-orphan"</literal>. The precise semantics of cascading operations
+            parent is <emphasis>not</emphasis> automatically deleted, except in the cases of 
+            <literal>&lt;one-to-many&gt;</literal> and <literal>&lt;one-to-one&gt;</literal> associations 
+            that have been mapped with <literal>cascade="all-delete-orphan"</literal> or 
+            <literal>cascade="delete-orphan"</literal>. The precise semantics of cascading operations
             are as follows:
         </para>
 
@@ -1081,8 +1082,8 @@ finally
                 <para>
                     If a transient child is dereferenced by a persistent parent, <emphasis>nothing
                     special happens</emphasis> (the application should explicitly delete the child if
-                    necessary) unless <literal>cascade="all-delete-orphan"</literal>, in which case the
-                    "orphaned" child is deleted.
+                    necessary) unless <literal>cascade="all-delete-orphan"</literal> or 
+                    <literal>cascade="delete-orphan"</literal>, in which case the "orphaned" child is deleted.
                 </para>
             </listitem>
         </itemizedlist>

src/NHibernate.Test/Cascade/OneToOneCascadeDelete/Hbm/Fk/Bidirectional/DeleteOneToOneOrphansTest.cs

@@ -0,0 +1,84 @@
+using NUnit.Framework;
+using System.Collections;
+
+namespace NHibernate.Test.Cascade.OneToOneCascadeDelete.Hbm.Fk.Bidirectional
+{
+	[TestFixture]
+	public class DeleteOneToOneOrphansTest : TestCase
+	{
+		protected override string MappingsAssembly
+		{
+			get { return "NHibernate.Test"; }
+		}
+
+		protected override IList Mappings
+		{
+			get { return new string[] { "Cascade.OneToOneCascadeDelete.Hbm.Fk.Bidirectional.Mappings.hbm.xml" }; }
+		}
+
+		protected override void OnSetUp()
+		{
+			base.OnSetUp();
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				var emp = new Employee();
+				emp.Info = new EmployeeInfo(emp);
+
+				s.Save(emp);
+				t.Commit();
+			}
+		}
+
+		protected override void OnTearDown()
+		{
+			base.OnTearDown();
+
+			using (var session = OpenSession())
+			using (var tx = session.BeginTransaction())
+			{
+				session.Delete("from EmployeeInfo");
+				session.Delete("from Employee");
+				tx.Commit();
+			}
+		}
+
+		[Test]
+		public void TestOrphanedWhileManaged()
+		{
+			long empId = 0;
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				var empInfoResults = s.CreateQuery("from EmployeeInfo").List<EmployeeInfo>();
+				Assert.AreEqual(1, empInfoResults.Count);
+
+				var empResults = s.CreateQuery("from Employee").List<Employee>();
+				Assert.AreEqual(1, empResults.Count);
+
+				var emp = empResults[0];
+				Assert.NotNull(emp);
+
+				empId = emp.Id;
+				emp.Info = null;
+				t.Commit();
+			}
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				var emp = s.Get<Employee>(empId);
+				Assert.Null(emp.Info);
+
+				var empInfoResults = s.CreateQuery("from EmployeeInfo").List<EmployeeInfo>();
+				Assert.AreEqual(0, empInfoResults.Count);
+
+				var empResults = s.CreateQuery("from Employee").List<Employee>();
+				Assert.AreEqual(1, empResults.Count);
+
+				t.Commit();
+			}
+		}
+	}
+}

src/NHibernate.Test/Cascade/OneToOneCascadeDelete/Hbm/Fk/Bidirectional/Mappings.hbm.xml

@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
+				assembly="NHibernate.Test"
+				namespace="NHibernate.Test.Cascade.OneToOneCascadeDelete.Hbm.Fk.Bidirectional" >
+
+	<class name="Employee">
+		<id name="Id" type="long" column="Id" >
+			<generator class="increment" />
+		</id>
+		<one-to-one name="Info"
+					property-ref="EmployeeDetails"
+					class="EmployeeInfo"
+					constrained="false"
+					cascade="all,delete-orphan" />
+	</class>
+
+	<class name="EmployeeInfo">
+		<id name="Id" type="long" column="Id" >
+			<generator class="increment" />
+		</id>
+		<many-to-one name="EmployeeDetails"
+					column="employee_id"
+					unique="true"
+					not-null="true" />
+	</class>
+
+</hibernate-mapping>

src/NHibernate.Test/Cascade/OneToOneCascadeDelete/Hbm/Fk/Bidirectional/Model.cs

@@ -0,0 +1,29 @@
+namespace NHibernate.Test.Cascade.OneToOneCascadeDelete.Hbm.Fk.Bidirectional
+{
+	public class Employee
+	{
+		public virtual long Id { get; set; }
+		public virtual EmployeeInfo Info { get; set; }
+
+		public Employee()
+		{
+
+		}
+	}
+
+	public class EmployeeInfo
+	{
+		public virtual long Id { get; set; }
+		public virtual Employee EmployeeDetails { get; set; }
+
+		public EmployeeInfo()
+		{
+
+		}
+
+		public EmployeeInfo(Employee emp)
+		{
+			EmployeeDetails = emp;
+		}
+	}
+}

src/NHibernate.Test/Cascade/OneToOneCascadeDelete/Hbm/Fk/Composite/DeleteOneToOneOrphansTest.cs

@@ -0,0 +1,84 @@
+using NUnit.Framework;
+using System.Collections;
+
+namespace NHibernate.Test.Cascade.OneToOneCascadeDelete.Hbm.Fk.Composite
+{
+	[TestFixture]
+	public class DeleteOneToOneOrphansTest : TestCase
+	{
+		protected override string MappingsAssembly
+		{
+			get { return "NHibernate.Test"; }
+		}
+
+		protected override IList Mappings
+		{
+			get { return new string[] { "Cascade.OneToOneCascadeDelete.Hbm.Fk.Composite.Mappings.hbm.xml" }; }
+		}
+
+		protected override void OnSetUp()
+		{
+			base.OnSetUp();
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				var emp = new Employee();
+				emp.Info = new EmployeeInfo( 1L, 1L);
+
+				s.Save(emp.Info);
+				s.Save(emp);
+				t.Commit();
+			}
+		}
+
+		protected override void OnTearDown()
+		{
+			base.OnTearDown();
+
+			using (var session = OpenSession())
+			using (var tx = session.BeginTransaction())
+			{
+				session.Delete("from EmployeeInfo");
+				session.Delete("from Employee");
+				tx.Commit();
+			}
+		}
+
+		[Test]
+		public void TestOrphanedWhileManaged()
+		{
+			long empId = 0;
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				var infoList = s.CreateQuery("from EmployeeInfo").List<EmployeeInfo>();
+				Assert.AreEqual(1, infoList.Count );
+
+				var empList = s.CreateQuery("from Employee").List<Employee>();
+				Assert.AreEqual(1, empList.Count);
+
+				var emp = empList[0];
+				Assert.NotNull(emp.Info);
+
+				empId = emp.Id;
+				emp.Info = null;
+
+				t.Commit();
+			}
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				var emp = s.Get<Employee>(empId);
+				Assert.IsNull(emp.Info);
+
+				var empInfoList = s.CreateQuery("from EmployeeInfo").List<EmployeeInfo>();
+				Assert.AreEqual(0, empInfoList.Count);
+
+				var empList = s.CreateQuery("from Employee").List<Employee>();
+				Assert.AreEqual(1, empList.Count);
+			}
+		}
+	}
+}

src/NHibernate.Test/Cascade/OneToOneCascadeDelete/Hbm/Fk/Composite/Mappings.hbm.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
+				assembly="NHibernate.Test"
+				namespace="NHibernate.Test.Cascade.OneToOneCascadeDelete.Hbm.Fk.Composite">
+
+	<class name="Employee">
+		<id name="Id" type="long" column="Id" >
+			<generator class="increment" />
+		</id>
+		<many-to-one name="Info"
+					unique="true"
+					not-found="exception"
+					cascade="all,delete-orphan" >
+			<column name="COMP_ID" />
+			<column name="PERS_ID" />
+		</many-to-one>
+	</class>
+
+	<class name="EmployeeInfo">
+		<composite-id class="EmployeeInfo+Identifier" name="Id" >
+			<key-property name="CompanyId" column="COMP_ID" />
+			<key-property name="PersonId" column="PERS_ID" />
+		</composite-id>
+	</class>
+
+</hibernate-mapping>

src/NHibernate.Test/Cascade/OneToOneCascadeDelete/Hbm/Fk/Composite/Model.cs

@@ -0,0 +1,82 @@
+using System;
+
+namespace NHibernate.Test.Cascade.OneToOneCascadeDelete.Hbm.Fk.Composite
+{
+	public class Employee
+	{
+		public virtual long Id { get; set; }
+		public virtual EmployeeInfo Info { get; set; }
+
+		public Employee()
+		{
+
+		}
+	}
+
+	public class EmployeeInfo
+	{
+		public class Identifier
+		{
+			public virtual long CompanyId { get; set; }
+			public virtual long PersonId { get; set; }
+
+			public Identifier()
+			{
+
+			}
+
+			public Identifier(long companyId, long personId)
+			{
+				this.CompanyId = companyId;
+				this.PersonId = personId;
+			}
+
+
+			public override bool Equals(Object o)
+			{
+				if (this == o)
+				{
+					return true;
+				}
+
+				var t = this.GetType();
+				var u = o.GetType();
+
+
+				if (o == null || !t.IsAssignableFrom(u) || !u.IsAssignableFrom(t))
+				{
+					return false;
+				}
+
+				var id = o as Identifier;
+
+				return CompanyId.Equals(id.CompanyId)
+						&& PersonId.Equals(id.PersonId);
+
+			}
+
+			public override int GetHashCode()
+			{
+				return (31 * CompanyId.GetHashCode()) + PersonId.GetHashCode();
+			}
+		}
+
+		public virtual Identifier Id { get; set; }
+		public virtual Employee Employee { get; set; }
+
+		public EmployeeInfo()
+		{
+
+		}
+
+		public EmployeeInfo(long companyId, long personId)
+		{
+			this.Id = new Identifier(companyId, personId);
+		}
+
+		public EmployeeInfo(Identifier id)
+		{
+			this.Id = id;
+		}
+	}
+}