protected virtual Expression BuildExecuteBatch(BatchExpression batch) { // parameterize query Expression operation = this.Parameterize(batch.Operation.Body); string commandText = this.linguist.Format(operation); var namedValues = NamedValueGatherer.Gather(operation); QueryCommand command = new QueryCommand(commandText, namedValues.Select(v => new QueryParameter(v.Name, v.Type, v.QueryType))); Expression[] values = namedValues.Select(v => Expression.Convert(this.Visit(v.Value), typeof(object))).ToArray(); Expression paramSets = Expression.Call(typeof(Enumerable), "Select", new Type[] { batch.Operation.Parameters[1].Type, typeof(object[]) }, batch.Input, Expression.Lambda(Expression.NewArrayInit(typeof(object), values), new[] { batch.Operation.Parameters[1] }) ); Expression plan = null; ProjectionExpression projection = ProjectionFinder.FindProjection(operation); if (projection != null) { var saveScope = this.scope; ParameterExpression reader = Expression.Parameter(typeof(FieldReader), "r" + nReaders++); this.scope = new Scope(this.scope, reader, projection.Select.Alias, projection.Select.Columns); LambdaExpression projector = Expression.Lambda(this.Visit(projection.Projector), reader); this.scope = saveScope; var entity = EntityFinder.Find(projection.Projector); command = new QueryCommand(command.CommandText, command.Parameters); plan = Expression.Call(this.executor, "ExecuteBatch", new Type[] { projector.Body.Type }, Expression.Constant(command), paramSets, projector, Expression.Constant(entity, typeof(MappingEntity)), batch.BatchSize, batch.Stream ); } else { plan = Expression.Call(this.executor, "ExecuteBatch", null, Expression.Constant(command), paramSets, batch.BatchSize, batch.Stream ); } return(plan); }
protected override Expression VisitBatch(BatchExpression batch) { if (this.linguist.Language.AllowsMultipleCommands || !IsMultipleCommands(batch.Operation.Body as CommandExpression)) { return(this.BuildExecuteBatch(batch)); } else { var source = this.Visit(batch.Input); var op = this.Visit(batch.Operation.Body); var fn = Expression.Lambda(op, batch.Operation.Parameters[1]); return(Expression.Call(this.GetType(), "Batch", new Type[] { TypeHelper.GetElementType(source.Type), batch.Operation.Body.Type }, source, fn, batch.Stream)); } }