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How to map recipes with ingredients using AutoMapper

I have following RecipeModel, IngredientModel and RecipePartModel classes which represent the DTO classes for the frontend user:
public class RecipeModel
{
public Guid Id { get; set; }
public string Name { get; set; }
public string ImageUrl { get; set; }
public string Description { get; set; }
public IEnumerable<RecipePartModel> RecipeParts { get; set; }
}
public class IngredientModel
{
public Guid Id { get; set; }
public string Name { get; set; }
}
public class RecipePartModel
{
public Guid Id { get; set; }
public IngredientModel Ingredient { get; set; }
public string Unit { get; set; }
public decimal Quantity { get; set; }
}
Here are my entity classes:
public class Recipe : BaseEntity
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[Key]
public Guid Id { get; set; }
public string Name { get; set; }
public string ImageUrl { get; set; }
public string Description { get; set; }
public virtual IEnumerable<RecipePart> RecipeParts { get; set; }
}
public class Ingredient : BaseEntity
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[Key]
public Guid Id { get; set; }
public string Name { get; set; }
public int Amount { get; set; }
public virtual IEnumerable<RecipePart> RecipeParts { get; set; }
}
public class RecipePart : BaseEntity
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[Key]
public Guid Id { get; set; }
public Ingredient Ingredient { get; set; }
public Recipe Recipe { get; set; }
public string Unit { get; set; }
public decimal Quantity { get; set; }
}
My question is - how can I map the Recipe to RecipeModel using AutoMapper? I tried something like this but I assume it is bad, because it just join all the RecipeParts for the whole database, am I correct?
public class DomainProfile : Profile
{
public DomainProfile()
{
CreateMap<Ingredient, IngredientModel>().ReverseMap();
CreateMap<Recipe, RecipeModel>()
.ForMember(x => x.RecipeParts, opt => opt.MapFrom(src => src.RecipeParts));
}
}

To answer your question about how to use AutoMapper to map a type to another type, there are many ways of doing this. Documentation is here: http://docs.automapper.org/en/stable/Getting-started.html.
I wrote a console app and got it working in the quickest way I know possible using your code. When I debug this, and check inside recipeModel, it references a list of RecipePartModels with a single RecipePartModel. Inside that RecipePartModel, it references an IngredientModel.
static void Main(string[] args)
{
var profile = new DomainProfile();
Mapper.Initialize(cfg => cfg.AddProfile(profile));
var recipe = new Recipe
{
RecipeParts = new List<RecipePart>
{
new RecipePart()
{
Ingredient = new Ingredient()
}
}
};
var recipeModel = Mapper.Map<Recipe, RecipeModel>(recipe);
Console.ReadKey();
}
To answer your concern about getting all recipes from the database, if you're using Entity Framework, it depends on if you have lazy loading turned on. Lazy loading ensures that, when you get a recipe from the database, the recipe parts will not be loaded. They will only be loaded when you access the recipe part directly later on in the program flow. Lazy loading is turned on by default so this is the default behaviour. If you turn it off, you've enabled eager loading which loads all recipe parts and in turn their ingredient.
This might help: http://www.entityframeworktutorial.net/lazyloading-in-entity-framework.aspx.

There is nothing bad about this mapping. In fact you don't even need the ForMember call as this is the default convention. The mapping will simply convert each element in the entity child collection to a corresponding model object.
Of course, whether you load your entities in an efficient manner is another matter. If you load a large amount of Recipe entities, and lazy load the RecipeParts collections for each, you will have a major "SELECT N+1" problem. But this is not the fault of AutoMapper.

Entity Framework Core filter related entities and get top 2 for each group

I am using Entity Framework Core 2.0.1 and I have the following models
public class Article
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[Key]
public int Id { get; set; }
[Required]
public string Title { get; set; }
public string Slug { get; set; }
public int Approved { get; set; }
public DateTime ArticleDate { get; set; }
// ... some other fields
public virtual ICollection<ArticleCategoryRelation> ArticleCategoryRelations { get; set; }
}
public class ArticleCategory
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
//... soem other fields
[ForeignKey("ArticleCategoryParent")]
public int? ArticleCategoryParentID { get; set; }
public virtual ArticleCategory ArticleCategoryParent { get; set; }
public virtual ICollection<ArticleCategory> SubCategories { get; set; }
public virtual ICollection<ArticleCategoryRelation> ArticleCategoryRelations { get; set; }
}
public class ArticleCategoryRelation
{
[Column(Order = 0)]
public int ArticleId { get; set; }
public Article Article { get; set; }
[Column(Order = 1)]
public int ArticleCategoryId { get; set; }
public ArticleCategory ArticleCategory {get; set;}
}
Every article belongs to one or more categories. Categories might have parent category.
I want to get from database last two articles (where Approved = 1) with related category details, for each category that belongs to a parent category which id is given as input.
I have tried but with no success. I can't filter results of an .Include() entity. Is it possible... or I don't know how to do it?
All my data are accessed through entity framework with appContext (the context used to get entities from database). Can I achieve what I want through entity framework core (lambda expression is preferred over Linq if possible), or should I use ADO.NET library (which I know how to execute custom queries).
P.S. I want to get data only to show in the view... no edit is needed.

You don't actually need to include here at all, as far as I can tell. Whenever you use data from a nav property, EF will go get the data from that table, as best it can filter it.
var CategoriesUnderParent = AppContext.ArticleCategories
.Where(c => c.ArticleCategoryParent == {parent});
foreach(var category in CategoriesUnderParent)
{
var ArticlesAllowed = category.ArticleCategoryRelations
.Where(acr => acr.Article.Approved == 1).Select(a => a.Article);
var ArticlesPicked = ArticlesAllowed
.OrderByDescending(ar => ar.ArticleDate)
.Take(2);
// Do something with your data
}

Dummy query to make recursive EFCore 2 properties load

I'm tearing my hair out trying to get my recursive EFCore objects to load all their grandparents/grandchildren and I can't decide if I'm being rubbish or I'm working around features which aren't working as desired.
A Link has a Category, which exists in a hierarchy of other Categories (the data structure works fine)
Link link = FP.Links.Include(a=>a.Transaction.Account.Home)
.Include(a=>a.Category)
.ThenInclude(b=>b.parent)
.AsEnumerable()
.Where(a=>a.TransId==_transId &&
a.Transaction.Account.Home==_authHome)
.FirstOrDefault();
When I look at the Link.Category.parent.parent it is null. It always seems to load the first couple of levels above, when I pull back a link whose category has more than 2 parents, it eventually gives me a null.
I've tried various SO answers which have guided me to use includes (which feels clunky) and the latest talks about .AsEnumerable(). I've tried FirstOrDefault() and SingleOrDefault().
I've got as far as: Loading in EFCore 2 is far from done, and that 'fixing up' is a thing. So, I tried adding:
List<Category> CL= FP.Categories.Where(a=>a.home==_authHome).ToList();
before the previous query and it works.
I have three questions:
1) Have I correctly interpreted that this forces my DBContext to have already loaded the data I need, and so it has access when I re-query?
2) Am I leaving myself open to this NOT working in some circumstances which testing wouldn't show me?
3) Is there any less inane way to make this same thing work?
(I may want link.Category.parent.parent.parent.(n).parent to all be accessible)
and a question that, knowing the rules of SO, I'll phrase rhetorically:
4) Is there any world in which this is desirable from a debugging/coding point of view????
Classes:
public class Link
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id {get; set;}
[ForeignKey("Transaction")]
public int TransId { get; set; }
public DateTime effectiveDt { get; set; }
public bool isRefund { get; set; }
public int transactionRole { get; set; }
public int setBy { get; set; }
public string transactionComment { get; set; }
public virtual Transaction Transaction { get; set; }
public virtual Category Category { get; set; }
}
public partial class Category
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id {get; set;}
public string Name { get; set; }
public int categoryType { get; set; } //0=Normal, 1=Savings, 2=Loan
[JsonIgnore]
public virtual Category parent { get; set; }
[JsonIgnore]
public virtual ICollection<Summary> summaries { get; set; }
public virtual ICollection<Category> children { get; set; }
[JsonIgnore]
public virtual ICollection<Link> Link { get; set; }
[JsonIgnore]
public virtual ICollection<Budget> Budget { get; set; }
[JsonIgnore]
public virtual Home home { get; set; }
}

EF Core does not track entity correctly

Hi I have problem with EF Core insert entity. The problem is that I need to insert new entity with relation to another one which is already existing. I have created the relations with fluent API. I have done this for two times. First I am creating car and adding the last edited by field with Identity user and all works but when I am trying to do the same with another entity it crashes down with
My fluent APi code which works good:
builder.Entity<Car>()
.HasOne(x => x.Owner)
.WithMany(x => x.OwnerCars)
.HasForeignKey(x => x.OwnerId);
Here is car entity:
public class Car : CarBase
{
[Key]
public int CarId { get; set; }
public bool IsTrailer { get; set; }
public virtual TrailerType TrailerType { get; set; }
public virtual int? TrailerTypeId { get; set; }
public virtual ApplicationUser Owner { get; set; }
public virtual string OwnerId { get; set; }
}
and here is Application user entity
public class ApplicationUser : IdentityUser
{
[MaxLength(100)]
public string Address { get; set; }
public DateTime CreatedDateTime { get; set; }
public DateTime LastEditationDateTime { get; set; }
public virtual ApplicationUser LastEditedBy { get; set; }
public bool IsDeleted { get; set; }
public virtual DateTime DeletedDateTime { get; set; }
public ICollection<DriverLicenseApplicationUser> DriverLicenses { get; set; }
public ICollection<RideApplicationUser> Rides { get; set; }
public ICollection<Car> OwnerCars { get; set; }
public ICollection<Car> EditedCars { get; set; }
public ICollection<Trailer> EditedTrailers { get; set; }
public ICollection<Customer> EditedCustomers { get; set; }
}
To add this entity I only call this function and all works.
public Car CreateCar(Car car)
{
_context.Cars.Add(car);
return car;
}
But when I want to save this way this another entity type it shows an error. All steps are same so I do not understand this. Here I am adding the code I use to do that.
builder.Entity<Trailer>()
.HasOne(x => x.TrailerType)
.WithMany(x => x.Trailers)
.HasForeignKey(x => x.TrailerTypeId);
Here is Trailer:
public class Trailer : CarBase
{
[Key]
public int TrailerId { get; set; }
//[Required]
public virtual TrailerType TrailerType { get; set; }
public virtual int TrailerTypeId { get; set; }
}
and here is traylerTyper:
public class TrailerType:Trackable
{
//[Key]
public int TrailerTypeId { get; set; }
[MaxLength(100)]
[Required]
public string Type { get; set; }
public string Note { get; set; }
public ICollection<Car> TrailerTypeCars { get; set; }
public ICollection<Trailer> Trailers{ get; set; }
}
and the method is the same as the one already mentioned
public Trailer CreateTrailer(Trailer trailer)
{
trailer.TrailerTypeId = trailer.TrailerType.TrailerTypeId;
//_context.Attach(trailer.TrailerType);
var result = _context.Trailers.Add(trailer);
return result.Entity;
}
When I uncomment the attach it works but I think that I dont have to attach this because I have got the relation based on IDs and the example mentioned first works great. It gives me no sense. So if anyone could give me advice it would be awsome.
Here is the error I am getting:
Cannot insert explicit value for identity column in table 'TrailerTypes' when IDENTITY_INSERT is set to OFF.
It looks like the EF doesnt know that the traylertype entity already exists and is trying to insert the same entity again and the app crashes because it already exists and I am not allowing to insert IDs directly. As I said I have absolutely no idea why is this happening.

The problem is Lazy loading. Propetry from ViewModel is not completly same as property in Database and EF tracks whole graph of property in object and doesn´t recognize that it is the same object. The solution is to work only with IDs instead with whole objects.

How to set up a complex many to many relationship in entity framework 4 code first

I have a relatively complex relationship I need to set up between a User object and a lot of lookup tables. The user object is your run of the mill user model:
public class Youth : IAuditInfo
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
public Guid YouthGuid { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public Address Address { get; set; }
public DateTime CreatedDate { get; set; }
public DateTime ModifiedDate { get; set; }
public string ImageName { get; set; }
[ForeignKey("FkYouthId")]
public ICollection<User> Parents { get; set; }
public CubPack Pack { get; set; }
public virtual ICollection<RequirementsLog> RequirementsLogs { get; set; }
public Youth()
{
Parents = new List<User>();
}
}
The lookup tables is where it gets complex and I can't figure out the path of least complexity in binding them together. For the lookups it is a series of tables starting with one 'master' table, that rolls down hierarchically to requirements and sub requirements, like this:
Master:
public class BearTrail
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
public string Name { get; set; }
public virtual ICollection<BearTrailRequiredBadge> BearTrailRequiredBadges { get; set; }
public virtual ICollection<BearTrailElectiveBadge> BearTrailElectivedBadges { get; set; }
}
Required Badges:
public class BearTrailRequiredBadge
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
public string Name { get; set; }
public int Number { get; set; }
public string Description { get; set; }
public virtual ICollection<BearTrailRequiredBadgeSubRequirement> BearTrailRequiredBadgeSubRequirements { get; set; }
}
Required Badge sub requirement:
public class BearTrailRequiredBadgeSubRequirement
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
public string Number { get; set; }
public string Text { get; set; }
public bool Required { get; set; }
}
This is one set of the lookups, there are about four nested classes like this, and some one off tables as well. Total lookup tables is about 16, give or take.
I was initially thinking if using my RequirementLog model to bind it:
public class RequirementsLog
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
public virtual ICollection<Youth> Youth { get; set; }
public BearTrail BearTrailRequirements { get; set; }
public TigerTrail TigerTrailRequirements { get; set; }
public WolfTrail WolfTrailRequirements { get; set; }
public WebelosTrail WebelosTrailRequirements { get; set; }
public WebelosArrowOfLight WebelosArrowOfLightRequirements { get; set; }
}
So there is a many to many between RequirementsLog and Youth. The table created out of RequirementsLog has one PK column (ID), and FK columns for each property. The many to many table created out of this (RequirementsLogYouths) has two PKs (RequirementsLogId, and YouthId).
Am I going about this the right way? The end goal is to have the 16 or so tables server as just lists of various requirements, and have another table(s) to track a particular youths progress through the requirements. I have a hard time visualizes some of this DBA stuff, so any input would be greatly appreciated.

In most cases, a requirements "log" be in a one (people) to many (the log).
Unless... One logged item is for many kids...
If so, the you need a third table, that maps many people to multiple logged events. That is, if this is truly a many to many. In general, that situation almost always begs for a third, intermediate mapping table. Read up a bit on many to many designs, and you'll quickly see it, and how simple it is.

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
modelBuilder.Entity<Entity1>()
.HasMany(b => b.Entities2)
.WithMany(p => p.Entities1)
.Map(m =>
{
m.ToTable("Entitie1Entity2");
m.MapLeftKey("Entity1Id");
m.MapRightKey("Entity2Id");
});
}