NH-3488 - Remove code duplication in DML queries

Author: hazzik

src/NHibernate/Linq/DefaultQueryProvider.cs

@@ -16,9 +16,7 @@ public interface INhQueryProvider : IQueryProvider
 		IEnumerable<TResult> ExecuteFuture<TResult>(Expression expression);
 		IFutureValue<TResult> ExecuteFutureValue<TResult>(Expression expression);
 		void SetResultTransformerAndAdditionalCriteria(IQuery query, NhLinqExpression nhExpression, IDictionary<string, Tuple<object, IType>> parameters);
-		int ExecuteDelete<T>(Expression predicate);
-		int ExecuteUpdate<T>(Expression expression, bool versioned);
-		int ExecuteInsert<T>(Expression expression);
+		int ExecuteDml<T>(QueryMode queryMode, Expression expression);
 	}
 
 	public class DefaultQueryProvider : INhQueryProvider
@@ -174,31 +172,9 @@ public virtual void SetResultTransformerAndAdditionalCriteria(IQuery query, NhLi
 			}
 		}
 
-		public int ExecuteDelete<T>(Expression predicate)
+		public int ExecuteDml<T>(QueryMode queryMode, Expression expression)
 		{
-			var nhLinqExpression = new NhLinqDeleteExpression(predicate, Session.Factory);
-
-			var query = Session.CreateQuery(nhLinqExpression);
-
-			SetParameters(query, nhLinqExpression.ParameterValuesByName);
-
-			return query.ExecuteUpdate();
-		}
-
-		public int ExecuteUpdate<T>(Expression expression, bool versioned)
-		{
-			var nhLinqExpression = new NhLinqUpdateExpression<T>(Session.Factory, expression, versioned);
-
-			var query = Session.CreateQuery(nhLinqExpression);
-
-			SetParameters(query, nhLinqExpression.ParameterValuesByName);
-
-			return query.ExecuteUpdate();
-		}
-
-		public int ExecuteInsert<T>(Expression expression)
-		{
-			var nhLinqExpression = new NhLinqInsertExpression<T>(Session.Factory, expression);
+			var nhLinqExpression = new NhLinqDmlExpression<T>(queryMode, expression, Session.Factory);
 
 			var query = Session.CreateQuery(nhLinqExpression);
 

src/NHibernate/Linq/InsertSyntax.cs

@@ -31,7 +31,7 @@ public int Into<TTarget>(Action<Assignments<TSource, TTarget>> assignmentActions
 			var assignments = new Assignments<TSource, TTarget>();
 			assignmentActions.Invoke(assignments);
 
-			return _provider.ExecuteInsert<TTarget>(DmlExpressionRewriter.PrepareExpression<TSource>(_sourceExpression, assignments.List));
+			return ExecuteInsert<TTarget>(DmlExpressionRewriter.PrepareExpression<TSource>(_sourceExpression, assignments.List));
 		}
 
 		/// <summary>
@@ -42,7 +42,12 @@ public int Into<TTarget>(Action<Assignments<TSource, TTarget>> assignmentActions
 		/// <returns>The number of inserted entities.</returns>
 		public int As<TTarget>(Expression<Func<TSource, TTarget>> expression)
 		{
-			return _provider.ExecuteInsert<TTarget>(DmlExpressionRewriter.PrepareExpression(_sourceExpression, expression));
+			return ExecuteInsert<TTarget>(DmlExpressionRewriter.PrepareExpression(_sourceExpression, expression));
+		}
+
+		private int ExecuteInsert<TTarget>(Expression insertExpression)
+		{
+			return _provider.ExecuteDml<TTarget>(QueryMode.Insert, insertExpression);
 		}
 	}
 }

src/NHibernate/Linq/LinqExtensionMethods.cs

@@ -141,7 +141,7 @@ public static IFutureValue<TResult> ToFutureValue<TSource, TResult>(this IQuerya
 		public static int Delete<TSource>(this IQueryable<TSource> source)
 		{
 			var provider = GetNhProvider(source);
-			return provider.ExecuteDelete<TSource>(source.Expression);
+			return provider.ExecuteDml<TSource>(QueryMode.Delete, source.Expression);
 		}
 
 		/// <summary>

src/NHibernate/Linq/NhLinqDeleteExpression.cs

@@ -0,0 +1,22 @@
+using System.Linq.Expressions;
+using NHibernate.Engine;
+
+namespace NHibernate.Linq
+{
+	public class NhLinqDmlExpression<T> : NhLinqExpression
+	{
+		protected override QueryMode QueryMode { get; }
+
+		/// <summary>
+		/// Entity type to insert or update when the expression is a DML.
+		/// </summary>
+		protected override System.Type TargetType => typeof(T);
+
+		public NhLinqDmlExpression(QueryMode queryMode, Expression expression, ISessionFactoryImplementor sessionFactory)
+			: base(expression, sessionFactory)
+		{
+			Key = $"{queryMode.ToString().ToUpperInvariant()} {Key}";
+			QueryMode = queryMode;
+		}
+	}
+}

src/NHibernate/Linq/NhLinqDmlExpression.cs

@@ -46,9 +46,9 @@ public int As(Expression<Func<T, T>> expression)
 			return ExecuteUpdate(DmlExpressionRewriter.PrepareExpression(_sourceExpression, expression));
 		}
 
-		private int ExecuteUpdate(Expression expression)
+		private int ExecuteUpdate(Expression updateExpression)
 		{
-			return _provider.ExecuteUpdate<T>(expression, _versioned);
+			return _provider.ExecuteDml<T>(_versioned ? QueryMode.UpdateVersioned : QueryMode.Update, updateExpression);
 		}
 	}
 }

src/NHibernate/Linq/NhLinqInsertExpression.cs

@@ -335,9 +335,7 @@
     <Compile Include="Linq\ReWriters\ArrayIndexExpressionFlattener.cs" />
     <Compile Include="Linq\Visitors\IQueryModelRewriterFactory.cs" />
     <Compile Include="Linq\QueryProviderFactory.cs" />
-    <Compile Include="Linq\NhLinqDeleteExpression.cs" />
-    <Compile Include="Linq\NhLinqInsertExpression.cs" />
-    <Compile Include="Linq\NhLinqUpdateExpression.cs" />
+    <Compile Include="Linq\NhLinqDmlExpression.cs" />
     <Compile Include="Linq\QueryMode.cs" />
     <Compile Include="Linq\Assignments.cs" />
     <Compile Include="Linq\UpdateSyntax.cs" />