QueryMappings

Query mappings provide simple strongly typed interface optimized for Entity Framework and IQueryable.

Motivation

As we use Entity Framework and IQueryable interface for a tons of different projects, we needed some naturally adaptable mapping interface to IQueryable interface. This interface should support possibility to pass arguments for more complicated mapping cases. Also there are cases when we can't have Navigation Property between objects or when we want to write LINQ syntax for queries, so we needed possibility to inject EF Context inside of the mapping.

Features

1. Simple and strongly typed mapping interface. Mappings API should be natural - we just map one object to another, we don't need 10 different methods just to do it:

_mappingsList.Add<Address, AddressModel>(x => new AddressModel { Id = x.Id, BuildingNumber = x.BuildingNumber, City = x.City, State = x.State, Country = (Countries)x.Country, Street = x.Street, ZipCode = x.ZipCode });

2. Oriented on Entity Framework. Best support of IQueryable and even injection of Entity Framework context inside of the mapping expression.

_mappingsList.Add<Building, BuildingStatisticsModel, BuildingArguments, IDbContext>(args => { return (query, context) => from building in query join review in context.Set<Review>() on new { EntityId = building.Id, EntityTypeId = (int)EntityType.Building } equals new { EntityId = review.EntityId, EntityTypeId = review.EntityTypeId } into reviews let address = building.Address select new BuildingStatisticsModel { Id = building.Id, Address = address.BuildingNumber + ", " + address.Street + ", " + address.City, AppartmentsCount = building.Appartments.Count(), Size = building.Appartments.Sum(app => app.Size), ResidentsCount = building.Appartments.SelectMany(app => app.Residents).Where(r => r.Age > args.TargetResidentsAge).Count(), AverageBuildingRating = reviews.Average(r => r.Rating) }; });