public IQueryable Bind(IQueryable query) { PreprocessQuery(query); // compute(X add Y as Z, A mul B as C) adds new properties to the output // Should return following expression // .Select($it => new ComputeWrapper<T> { // Instance = $it, // Container => new AggregationPropertyContainer() { // Name = "X", // Value = $it.X + $it.Y, // Next = new LastInChain() { // Name = "C", // Value = $it.A * $it.B // } // }) List <MemberAssignment> wrapperTypeMemberAssignments = new List <MemberAssignment>(); // Set Instance property var wrapperProperty = this.ResultClrType.GetProperty("Instance"); wrapperTypeMemberAssignments.Add(Expression.Bind(wrapperProperty, this._lambdaParameter)); var properties = new List <NamedPropertyExpression>(); foreach (var computeExpression in this._transformation.ComputeClause.ComputedItems) { properties.Add(new NamedPropertyExpression(Expression.Constant(computeExpression.Alias), CreateComputeExpression(computeExpression))); } // Set new compute properties wrapperProperty = ResultClrType.GetProperty("Container"); wrapperTypeMemberAssignments.Add(Expression.Bind(wrapperProperty, AggregationPropertyContainer.CreateNextNamedPropertyContainer(properties))); var initilizedMember = Expression.MemberInit(Expression.New(ResultClrType), wrapperTypeMemberAssignments); var selectLambda = Expression.Lambda(initilizedMember, this._lambdaParameter); var result = ExpressionHelpers.Select(query, selectLambda, this._elementType); return(result); }
private List <NamedPropertyExpression> CreateGroupByMemberAssignments(IEnumerable <GroupByPropertyNode> nodes) { var properties = new List <NamedPropertyExpression>(); foreach (var grpProp in nodes) { var propertyName = grpProp.Name; if (grpProp.Expression != null) { properties.Add(new NamedPropertyExpression(Expression.Constant(propertyName), WrapConvert(BindAccessor(grpProp.Expression)))); } else { var wrapperProperty = typeof(GroupByWrapper).GetProperty("GroupByContainer"); List <MemberAssignment> wta = new List <MemberAssignment>(); wta.Add(Expression.Bind(wrapperProperty, AggregationPropertyContainer.CreateNextNamedPropertyContainer(CreateGroupByMemberAssignments(grpProp.ChildTransformations)))); properties.Add(new NamedPropertyExpression(Expression.Constant(propertyName), Expression.MemberInit(Expression.New(typeof(GroupByWrapper)), wta))); } } return(properties); }
private IQueryable BindGroupBy(IQueryable query) { LambdaExpression groupLambda = null; Type elementType = query.ElementType; if (_groupingProperties != null && _groupingProperties.Any()) { // Generates expression // .GroupBy($it => new DynamicTypeWrapper() // { // GroupByContainer => new AggregationPropertyContainer() { // Name = "Prop1", // Value = $it.Prop1, // Next = new AggregationPropertyContainer() { // Name = "Prop2", // Value = $it.Prop2, // int // Next = new LastInChain() { // Name = "Prop3", // Value = $it.Prop3 // } // } // } // }) List <NamedPropertyExpression> properties = CreateGroupByMemberAssignments(_groupingProperties); var wrapperProperty = typeof(GroupByWrapper).GetProperty(GroupByContainerProperty); List <MemberAssignment> wta = new List <MemberAssignment>(); wta.Add(Expression.Bind(wrapperProperty, AggregationPropertyContainer.CreateNextNamedPropertyContainer(properties))); groupLambda = Expression.Lambda(Expression.MemberInit(Expression.New(typeof(GroupByWrapper)), wta), _lambdaParameter); } else { // We do not have properties to aggregate // .GroupBy($it => new NoGroupByWrapper()) groupLambda = Expression.Lambda(Expression.New(this._groupByClrType), this._lambdaParameter); } return(ExpressionHelpers.GroupBy(query, groupLambda, elementType, this._groupByClrType)); }
/// <summary> /// Pre flattens properties referenced in aggregate clause to avoid generation of nested queries by EF. /// For query like groupby((A), aggregate(B/C with max as Alias1, B/D with max as Alias2)) we need to generate /// .Select( /// $it => new FlattenninWrapper () { /// Source = $it, // Will used in groupby stage /// Container = new { /// Value = $it.B.C /// Next = new { /// Value = $it.B.D /// } /// } /// } /// ) /// Also we need to populate expressions to access B/C and B/D in aggregate stage. It will look like: /// B/C : $it.Container.Value /// B/D : $it.Container.Next.Value /// </summary> /// <param name="query"></param> /// <returns>Query with Select that flattens properties</returns> private IQueryable FlattenReferencedProperties(IQueryable query) { if (_aggregateExpressions != null && _aggregateExpressions.Any(e => e.Method != AggregationMethod.VirtualPropertyCount) && _groupingProperties != null && _groupingProperties.Any() && (FlattenedPropertyContainer == null || !FlattenedPropertyContainer.Any()) ) { var wrapperType = typeof(FlatteningWrapper <>).MakeGenericType(this._elementType); var sourceProperty = wrapperType.GetProperty("Source"); List <MemberAssignment> wta = new List <MemberAssignment>(); wta.Add(Expression.Bind(sourceProperty, this._lambdaParameter)); var aggrregatedPropertiesToFlatten = _aggregateExpressions.Where(e => e.Method != AggregationMethod.VirtualPropertyCount).ToList(); // Generated Select will be stack like, meaning that first property in the list will be deepest one // For example if we add $it.B.C, $it.B.D, select will look like // new { // Value = $it.B.C // Next = new { // Value = $it.B.D // } // } // We are generated references (in currentContainerExpression) from the begining of the Select ($it.Value, then $it.Next.Value etc.) // We have proper match we need insert properties in reverse order // After this // properties = { $it.B.D, $it.B.C} // _preFlattendMAp = { {$it.B.C, $it.Value}, {$it.B.D, $it.Next.Value} } var properties = new NamedPropertyExpression[aggrregatedPropertiesToFlatten.Count]; var aliasIdx = aggrregatedPropertiesToFlatten.Count - 1; var aggParam = Expression.Parameter(wrapperType, "$it"); var currentContainerExpression = Expression.Property(aggParam, GroupByContainerProperty); foreach (var aggExpression in aggrregatedPropertiesToFlatten) { var alias = "Property" + aliasIdx; // We just need unique alias, we aren't going to use it // Add Value = $it.B.C var propAccessExpression = BindAccessor(aggExpression.Expression); var type = propAccessExpression.Type; propAccessExpression = WrapConvert(propAccessExpression); properties[aliasIdx] = new NamedPropertyExpression(Expression.Constant(alias), propAccessExpression); // Save $it.Container.Next.Value for future use UnaryExpression flatAccessExpression = Expression.Convert( Expression.Property(currentContainerExpression, "Value"), type); currentContainerExpression = Expression.Property(currentContainerExpression, "Next"); _preFlattenedMap.Add(aggExpression.Expression, flatAccessExpression); aliasIdx--; } var wrapperProperty = ResultClrType.GetProperty(GroupByContainerProperty); wta.Add(Expression.Bind(wrapperProperty, AggregationPropertyContainer.CreateNextNamedPropertyContainer(properties))); var flatLambda = Expression.Lambda(Expression.MemberInit(Expression.New(wrapperType), wta), _lambdaParameter); query = ExpressionHelpers.Select(query, flatLambda, this._elementType); // We applied flattening let .GroupBy know about it. this._lambdaParameter = aggParam; this._elementType = wrapperType; } return(query); }