protected ClientJoinExpression UpdateClientJoin(ClientJoinExpression join, ProjectionExpression projection, IEnumerable <Expression> outerKey, IEnumerable <Expression> innerKey) { if (projection != join.Projection || outerKey != join.OuterKey || innerKey != join.InnerKey) { return(new ClientJoinExpression(projection, outerKey, innerKey)); } return(join); }
protected virtual Expression VisitClientJoin(ClientJoinExpression join) { var projection = (ProjectionExpression)Visit(join.Projection); ReadOnlyCollection <Expression> outerKey = VisitExpressionList(join.OuterKey); ReadOnlyCollection <Expression> innerKey = VisitExpressionList(join.InnerKey); return(UpdateClientJoin(join, projection, outerKey, innerKey)); }
protected override Expression VisitClientJoin(ClientJoinExpression join) { ReadOnlyCollection <Expression> innerKey = VisitExpressionList(join.InnerKey); ReadOnlyCollection <Expression> outerKey = VisitExpressionList(join.OuterKey); var projection = (ProjectionExpression)Visit(join.Projection); if (projection != join.Projection || innerKey != join.InnerKey || outerKey != join.OuterKey) { return(new ClientJoinExpression(projection, outerKey, innerKey)); } return(join); }
protected override Expression VisitClientJoin(ClientJoinExpression join) { // treat client joins as new top level bool saveTop = isTopLevel; SelectExpression saveSelect = currentSelect; isTopLevel = true; currentSelect = null; Expression result = base.VisitClientJoin(join); isTopLevel = saveTop; currentSelect = saveSelect; return(result); }
protected override Expression VisitClientJoin(ClientJoinExpression join) { // convert client join into a up-front lookup table builder & replace client-join in tree with lookup accessor // 1) lookup = query.Select(e => new KVP(key: inner, value: e)).ToLookup(kvp => kvp.Key, kvp => kvp.Value) Expression innerKey = MakeJoinKey(join.InnerKey); Expression outerKey = MakeJoinKey(join.OuterKey); ConstructorInfo kvpConstructor = typeof(KeyValuePair <,>).MakeGenericType(innerKey.Type, join.Projection.Projector.Type).GetConstructor(new[] { innerKey.Type, join.Projection.Projector.Type }); Expression constructKVPair = Expression.New(kvpConstructor, innerKey, join.Projection.Projector); var newProjection = new ProjectionExpression(join.Projection.Select, constructKVPair); int iLookup = ++nLookup; Expression execution = ExecuteProjection(newProjection, false); ParameterExpression kvp = Expression.Parameter(constructKVPair.Type, "kvp"); // filter out nulls if (join.Projection.Projector.NodeType == (ExpressionType)DbExpressionType.OuterJoined) { LambdaExpression pred = Expression.Lambda(Expression.PropertyOrField(kvp, "Value").NotEqual(TypeHelper.GetNullConstant(join.Projection.Projector.Type)), kvp); execution = Expression.Call(typeof(Enumerable), "Where", new[] { kvp.Type }, execution, pred); } // make lookup LambdaExpression keySelector = Expression.Lambda(Expression.PropertyOrField(kvp, "Key"), kvp); LambdaExpression elementSelector = Expression.Lambda(Expression.PropertyOrField(kvp, "Value"), kvp); Expression toLookup = Expression.Call(typeof(Enumerable), "ToLookup", new[] { kvp.Type, outerKey.Type, join.Projection.Projector.Type }, execution, keySelector, elementSelector); // 2) agg(lookup[outer]) ParameterExpression lookup = Expression.Parameter(toLookup.Type, "lookup" + iLookup); PropertyInfo property = lookup.Type.GetProperty("Item"); Expression access = Expression.Call(lookup, property.GetGetMethod(), Visit(outerKey)); if (join.Projection.Aggregator != null) { // apply aggregator access = DbExpressionReplacer.Replace(join.Projection.Aggregator.Body, join.Projection.Aggregator.Parameters[0], access); } variables.Add(lookup); initializers.Add(toLookup); return(access); }
protected virtual Expression VisitClientJoin(ClientJoinExpression join) { AddAlias(join.Projection.Select.Alias); Write("ClientJoin("); WriteLine(Indentation.Inner); Write("OuterKey("); VisitExpressionList(join.OuterKey); Write("),"); WriteLine(Indentation.Same); Write("InnerKey("); VisitExpressionList(join.InnerKey); Write("),"); WriteLine(Indentation.Same); Visit(join.Projection); WriteLine(Indentation.Outer); Write(")"); return(join); }