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.
Related
I am having an issue with EF returning NULL values within a child list. Here is my model that I am trying to get:
public class CompoundIngredient : Ingredient
{
public List<MeasuredIngredient> MeasuredIngredients { get; set; }
public string UserId { get; set; }
public CompoundIngredient()
{
MeasuredIngredients = new List<MeasuredIngredient>();
IsPublic = true;
}
}
However, when I do this:
return await _dataContext.CompoundIngredients
.Include(a => a.MeasuredIngredients)
.ThenInclude(a => a.MeasurementType)
.Include(a => a.MeasuredIngredients)
.ThenInclude(a => a.Ingredient)
.ThenInclude(a => a.IngredientType)
.FirstOrDefaultAsync(c => c.DisplayValue == name);
I get back a collection of 4 items. 2 items are populated and 2 are NULL.
Here is the data in the DB
As you can see from the picture there are 4 entries in the table, 2 of which belong to CompoundIngredientId 6 which is the ID of the ingredient who matches the Name value.
Why am I getting 4 results back, 2 of which are null?
EDIT:
So here are the models
public class CompoundIngredient : Ingredient
{
public List<MeasuredIngredient> MeasuredIngredients { get; set; }
public string UserId { get; set; }
public CompoundIngredient()
{
MeasuredIngredients = new List<MeasuredIngredient>();
IsPublic = true;
}
}
public class Ingredient
{
public int Id { get; set; }
public string DisplayValue { get; set; }
public string Description { get; set; }
public bool IsPublic { get; set; }
public IngredientType IngredientType { get; set; }
public int IngredientTypeId { get; set; }
public int CompanyId { get; set; }
public string UserName { get; set; }
public string CreatedBy { get; set; }
public DateTime CreatedDate { get; set; }
public string LastModifiedBy { get; set; }
public DateTime LastModifiedDate { get; set; }
}
public class MeasuredIngredient
{
public int Id { get; set; }
public decimal Amount { get; set; }
public int MeasurementTypeId { get; set; }
public MeasurementType MeasurementType { get; set; }
public int IngredientId { get; set; }
public Ingredient Ingredient { get; set; }
public int? UseId { get; set; }
public Use Use { get; set; }
}
public class Recipe
{
public int Id { get; set; }
public string UserId { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public bool IsPublic { get; set; }
public int RecipeCategoryId { get; set; }
public RecipeCategory RecipeCategory { get; set; }
public int SocialMediaId { get; set; }
public SocialMedia SocialMedia { get; set; }
public virtual List<TimeTemp> TimeTemps { get; set; }
public virtual List<RecipeFuel> RecipeFuels{ get;set; }
public List<MeasuredIngredient> MeasuredIngredients { get; set; }
public List<RecipeStep> RecipeSteps { get; set; }
public string CreatedBy { get; set; }
public DateTime CreatedDate { get; set; }
public string LastModifiedBy { get; set; }
public DateTime LastModifiedDate { get; set; }
public Recipe()
{
MeasuredIngredients = new List<MeasuredIngredient>();
RecipeSteps = new List<RecipeStep>();
SocialMedia = new SocialMedia();
RecipeFuels = new List<RecipeFuel>();
TimeTemps = new List<TimeTemp>();
IsPublic = true;
}
}
As you can see Measured Ingredient isnt exclusive to CompoundIngredient. Recipe also has a List on it as well.
as far as configurations i dont have much
public class MeasuredIngredientConfiguration : IEntityTypeConfiguration<MeasuredIngredient>
{
public void Configure(EntityTypeBuilder<MeasuredIngredient> builder)
{
builder.Property(p => p.UseId).IsRequired(false);
}
}
public class IngredientConfiguration : IEntityTypeConfiguration<Ingredient>
{
public void Configure(EntityTypeBuilder<Ingredient> builder)
{
builder.Property(p => p.IsPublic).HasDefaultValue(true);
}
}
public class RecipeConfiguration : IEntityTypeConfiguration<Recipe>
{
public void Configure(EntityTypeBuilder<Recipe> builder)
{
builder.Property(p => p.IsPublic).HasDefaultValue(true);
}
}
here are the tables in the DB with FKs
I highly suspect the issue will stem from CompoundIngredient inheriting from Ingredient using TPH inheritance (One table with a Discriminator) then being referenced by MeasuredIngredient, and this relationship not being set up quite right. Which version of EF Core is this?
Overall the relationship between these entities/tables feels "odd". You have an ingredient, then a "compound" ingredient that is made up of one or more MeasuredIngredient. (which does not extend ingredient) A Measured ingredient contains one Ingredient, and optionally one CompoundIngredient.
Given a compound ingredient represents just a collection of measured ingredients, this just feels a bit off. It sounds like you want a recipe to contain a list of ingredients where each is associated with a measurement (The MeasuredIngredient) but that "ingredient" may be a combination of other ingredients (with associated measurements) where you may want to possibly avoid duplicating data.
I built a simple test with the core relationships in EF Core 5 and I was able to get the expected results. The important detail here was ensuring the relationship between the 3 classes (and possibly other related classes) is configured correctly. For example, cutting down the object model down to the core I came up with:
public class Ingredient
{
public int Id { get; set; }
public string Name { get; set; }
}
public class CompoundIngredient : Ingredient
{
public virtual ICollection<MeasuredIngredient> MeasuredIngredients { get; set; } = new List<MeasuredIngredient>();
}
public class MeasuredIngredient
{
public int Id { get; set; }
publi int IngredientId { get; set; }
public virtual Ingredient Ingredient { get; set; }
}
Creating test records with the relationships you showed and running EF Core 5 I wasn't able to reproduce the issue, but I honestly did not feel comfortable with leaving EF to sort out the discriminator and relationships.
The bits I didn't like were:
CompoundIngredient extends Ingredient while containing a Many relationship to MeasuredIngredient where there is no corresponding "One" relationship on MeasuredIngredient, but it does have a "One" relationship with Ingredient.
The discriminator here is implied, not configured.
What I am more comfortable with was:
public class Ingredient
{
public int Id { get; set; }
public string Name { get; set; }
}
public class CompoundIngredient : Ingredient
{
public virtual ICollection<MeasuredIngredient> MeasuredIngredients { get; set; } = new List<MeasuredIngredient>();
}
public class MeasuredIngredient
{
public int Id { get; set; }
public virtual Ingredient Ingredient { get; set; }
public virtual CompoundIngredient CompoundIngredient { get; set; }
}
Then explicitly mapping the relationships to ensure there is no confusion on FKs:
public class MeasuredIngredientConfiguration : IEntityTypeConfiguration<MeasuredIngredient>
{
public void Configure(EntityTypeBuilder<MeasuredIngredient> builder)
{
builder.Property(p => p.UseId).IsRequired(false);
builder.HasOne(p => p.Ingredient)
.WithMany()
.IsRequired()
.HasForeignKey("IngredientId");
builder.HasOne(p => p.CompoundIngredient)
.WithMany(p => p.MeasuredIngredients)
.IsRequired(false)
.HasForeignKey("CompoundIngredientId");
}
}
public class IngredientConfiguration : IEntityTypeConfiguration<Ingredient>
{
public void Configure(EntityTypeBuilder<Ingredient> builder)
{
builder.Property(p => p.IsPublic).HasDefaultValue(true);
builder.HasDiscriminator<string>("Discriminator")
.HasValue<Ingredient>("I")
.HasValue<CompoundIngredient>("C"); // Whichever discriminator values you want to use.
}
}
I generally do not have FKs exposed in entities for navigation properties, opting for shadow properties. This should work just as well with the FK fields mapped.
Now I had excluded this configuration and this example did work with EF Core 5. I was also trying to force a misconfiguration around possibly the CompoundIngredientId and IngredientId in the measured ingredient, but outside of generating specific configuration errors around missing assumed FKs I wasn't able to reproduce your issue. It could also be behaviour specific to the version of EF Core you are using.
You could try adding the explicit mapping to see if that solves or otherwise changes your results. Getting null entries in your collection smells like EF is trying to parse the CompoundIngredient -> MeasuredIngredient, but it is getting other measured Ingredients with the same Ingredient reference (1-2) but not the matching compound ingredient ID. It's definitely a weird one.
Otherwise I would look to temporarily eliminate all other references such as Recipe, measurement type, etc. down to the simplest possible example and data set that reproduces the problem. This becomes easier to investigate options to identify where/what is getting mixed up.
Hopefully this gives you some ideas on how to get to the bottom of the issue.
Turns out the issue is not with EF… after looking further into it EF is returning the proper counts and relations. The issue is higher up during the deserialization of the json being returned from the API. I created a new question for this
JsonSerializer.DeserializeAsync<> Creating Null Items in Collections
I'm trying to make an insert in a SQL database using Entity Framework 6 and I'm stuck on this issue that I cannot solve.
The error that I keep getting is :
UpdateException: Entities in 'Connect.CompanyFinancialDetails' participate in the 'Company_CompanyFinancialDetails' relationship. 0 related 'Company_CompanyFinancialDetails_Source' were found. 1 'Company_CompanyFinancialDetails_Source' is expected
I have these 2 entities:
public class Company
{
public long CUI { get; set; }
public string UserName { get; set; }
public string CompanyName { get; set; }
public string Symbol { get; set; }
public int? SharesCount { get; set; }
public decimal? SharePrice { get; set; }
public virtual Account Account { get; set; }
public virtual CompanyFinancialDetails CompanyFinancialDetails { get; set; }
}
public class CompanyFinancialDetails
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
// other properties
public decimal? NumberOfEmployees { get; set; }
public virtual Company Company { get; set; }
}
This is the Fluent API configuration:
public DbSet<Account> SignUpModels { get; set; }
public DbSet<Company> Companies { get; set; }
public DbSet<CompanyFinancialDetails> CompanyFinancialDetails { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Account>()
.HasKey(k => k.Id)
.HasOptional(s => s.Company)
.WithRequired(d => d.Account);
modelBuilder.Entity<Company>()
.HasKey(k => k.CUI)
.HasOptional(s => s.CompanyFinancialDetails)
.WithRequired(d => d.Company);
}
The relationship that I want to have is 1-many (one Company has many CompanyFinancialDetails).
This is the code where I add the objects to the database:
Company co = Context.Find(username);
foreach (CompanyFinancialDetails s in c)
{
s.Company = co;
}
a.CompanyFinancialDetails.AddRange(c);
a.SaveChanges();
I get a list of CompanyFinancialDetails and I add them using the AddRange method. I had this issue before and what I did was to add the virtual property object to the object that I wanted to insert in the database and it worked. This is what I tried to do here: the Find() method gets the company object that is related to the CompanyFinancialDetails and for each CompanyFinancialDetails object an Company virtual property is adding the related company object.
Well, it didn't work, when the SaveChanges() method is called, I get that error. Any help would be appreciated.
This is a operation i have done many times in the past using database-first approach. I'm now trying it with code-first using EF Core and i'm failing horribly.
I have the following model:
public class DataMapping
{
[Key]
[Column(Order = 1)]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public long Id { get; set; }
public string Model { get; set; }
public string Property { get; set; }
public bool IgnoreProperty { get; set; }
[NotMapped] //<-- I had to add this as the migration was complaining that it did not know what the relation was
public List<DataMappingRelation> DataMappingRelations { get; set; }
public DateTime DateCreated { get; set; } = DateTime.UtcNow;
public DateTime? DateModified { get; set; }
}
and a Bridge model that basically creates a relations between two DataMapping items in the same table:
public class DataMappingRelation
{
[Key]
[Column(Order = 1)]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public long Id { get; set; }
[ForeignKey("DataMappingId")]
public long? DataMapping1Id { get; set; }
public DataMapping DataMapping1 { get; set; }
[ForeignKey("DataMappingId")]
public long? DataMapping2Id { get; set; }
public DataMapping DataMapping2 { get; set; }
}
However this call does not work:
return _context.DataMappings.Where(x => x.Model == type.FullName)
.Include(x=>x.DataMappingRelations)
.ToList();
It does not like the Include and throws a null ref exception.
All i basically need to do here is for a given "DataMapping" get all the related DataMapping items based on the relations in the "DataMappingRelations" table.
Yes i have looked at this answer but again, it is an example of two seperate tables, not a single table bridging on itself.
I suspect i have done all of this wrong. How can i get this to work? All the examples i have found are bridging two seperate tables. this would be bridging the same table.
Its many-to-many with self but your whole configuration looks messy.
So first, your DataMapping model class should contain two list navigation properties for two foreign keys in the DataMappingRelation as follows:
public class DataMapping
{
......
public List<DataMappingRelation> DataMapping1Relations { get; set; }
public List<DataMappingRelation> DataMapping2Relations { get; set; }
.........
}
Now remove [ForeignKey("DataMappingId")] attribute from both DataMapping1 and DataMapping2 foreign keys as follows:
public class DataMappingRelation
{
[Key]
[Column(Order = 1)]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public long Id { get; set; }
public long? DataMapping1Id { get; set; }
public DataMapping DataMapping1 { get; set; }
public long? DataMapping2Id { get; set; }
public DataMapping DataMapping2 { get; set; }
}
Then the Fluent API configuration should be as follows:
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Entity<DataMappingRelation>()
.HasOne(dmr => dmr.DataMapping1)
.WithMany(dm => dm.DataMapping1Relations)
.HasForeignKey(dmr => dmr.DataMapping1Id)
.OnDelete(DeleteBehavior.Restrict);
modelBuilder.Entity<DataMappingRelation>()
.HasOne(dmr => dmr.DataMapping2)
.WithMany(dm => dm.DataMapping2Relations)
.HasForeignKey(dmr => dmr.DataMapping2Id)
.OnDelete(DeleteBehavior.Restrict);
}
I have a .net core 2.0 project using .netcore identity' .
I have a classApplicationUser'(aka Owner) and 3 other classes of media objects Videos, Images, and Audio ("Clips"). So far all is great. where i am hitting a wall is when i try to refactor so that rather than having to hit the DB and say something like:
user=_usermanager.getuserasync(User)
images= _context.Images.Where(i=>i.i.Owner.username== user.username)
I would like to be able to access the same thing by simply saying
user.images
which would hopefully allow me to say things like :'foreach (Audio clip in User.Clips){//do the hokeypokee//}
so i modified my ApplicationUser class to include an ICollection<Type> for each of my media classes. No matter what i do however when i access user.images etc i always get null.(tried virtual nav props as well)
rather than sitting here explaining what i THINK it is (Something im not doing with the getter and setter perhaps?) which would be confusing i figure I just let you guys tell me what direction,I should be going in because I've been down many rabbit holes now trying to figure this out. Entity framework seems in order its just something im not doing ... i cant even figure out (if not in EF somewhere) how the setter is initially defined meaning how does it know what images belong to the user without querying the database to see which images have the fk that much the user... anyway the more i type the more i confuse myself LOL.
User Class:
public class ApplicationUser : IdentityUser, ITraits
{
public int Age { get; set; }
public Ethnicity Ethnicity { get; set; }
public Color EyeColor { get; set; }
public Color HairColor { get; set; }
public int Height { get; set; }
public Race Race { get; set; }
public CuckRole CuckRole { get; set; }
public BiologicalSex BiologicalSex { get; set; }
public Sexuality Sexuality { get; set; }
public Color SkinColor { get; set; }
public int Weight { get; set; }
public DateTime BirthDay { get; set; }
public ICollection<Image> Images { get; set; }
public ICollection<Audio> Clips { get; set; }
public ICollection<Video> Videos { get; set; }
public bool Equals(Traits other) => throw new NotImplementedException();
}
and then my media class (just one all the same just different names)
public class Audio
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Guid Id { get; set; }
public string Name { get; set; }
public string Path { get; set; }
public ApplicationUser Owner { get; set; }
//Constructors//
public Audio()
{
}
public Audio(string path,ApplicationUser owner)
{
Path = path;
Owner = owner;
}
}
EDIT
ok so i tried to implement the suggested code as best i could and thus far this is what i've come up with :
Media Class :
public class Audio
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Guid Id { get; set; }
public string Name { get; set; }
public string Path { get; set; }
public ApplicationUser Owner { get; set; }
public string OwnerId { get; set; }
//Constructors//
public Audio()
{
}
public Audio(string path,ApplicationUser owner)
{
Path = path;
Owner = owner;
}
}
and my ApplicationUser Class now looks like this :
public class ApplicationUser : IdentityUser, ITraits
{
public int Age { get; set; }
public Ethnicity Ethnicity { get; set; }
public Color EyeColor { get; set; }
public Color HairColor { get; set; }
public int Height { get; set; }
public Race Race { get; set; }
public CuckRole CuckRole { get; set; }
public BiologicalSex BiologicalSex { get; set; }
public Sexuality Sexuality { get; set; }
public Color SkinColor { get; set; }
public int Weight { get; set; }
public DateTime BirthDay { get; set; }
public ICollection<Image> Images { get; set; }
public ICollection<Audio> Clips { get; set; }
public ICollection<Video> Videos { get; set; }
public bool Equals(Traits other) => throw new NotImplementedException();
}
and finally my DBContext :
public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
{
public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
: base(options)
{
}
public DbSet<Cucklist.Models.Image> Images { get; set; }
public DbSet<Cucklist.Models.Video> Videos { get; set; }
public DbSet<Cucklist.Models.Audio> Clips { get; set; }
protected override void OnModelCreating(ModelBuilder builder)
{
base.OnModelCreating(builder);
builder.Entity<Image>().ToTable("Image")
.HasOne(Image => Image.Owner)
.WithMany(Owner => Owner.Images)
.HasForeignKey(Image => Image.OwnerId);
builder.Entity<Video>().ToTable("Video")
.HasOne(Video => Video.Owner)
.WithMany(Owner => Owner.Videos)
.HasForeignKey(Video =>Video.OwnerId );
builder.Entity<Audio>().ToTable("Clips")
.HasOne(Audio => Audio.Owner)
.WithMany(Owner => Owner.Clips)
.HasForeignKey(Audio =>Audio.OwnerId );
}
}
sadly i still get a null when accessing user.media (image,video etc)
Hey Guys thanks again for your help (#nilsK) - so the answer ended up being an entity framework "Thing".
Basically lazy loading isn't supported in Entity Framework Core until v2.1 which is in preview now (not sure if i missed making sure to specify it was entity framework core but i guessed that all assumed since it is a .net core project and you have to use Ef Core for a .net core project.) at any rate even with the Microsoft.EntityFrameworkCore updated and installed 2.1.0-previewfinal-2 it still doesn't work .
In order for it to "work" In Other words- not pull back a null when trying to access related entities you must also install the package Microsoft.EntityFramworkCore.Proxies.
Actually this is the easiest way(According to MS) to "enable" lazy loading in ef core; using the proxies. Although two other methods are available that are much more involved to implement
here is the link to the article that finally answered this question once and for all : https://learn.microsoft.com/en-us/ef/core/querying/related-data
so the short and skinny is once you installed the packages you have to (should for above option ) make all call to .UseLazyLoadingProxies() option in your DI container -- go to startup.cs and modify the DBContext options adding .UseLazyLoadingProixes() before the .UseSqlServer(...) and that's it....
now when you instantiate an entity with related entities they will be loaded on first access to the property... so basically It will stop returning a null!!!
otherwise you'd have to use implicit include statements etc... eager loading isnt and option but rather per query declarations...
Summary:
Step 1: Install Microsoft.EntityFrameworkCore preview 2.1.xx
Step 2: Install Microsoft.EntityFrameworkCore.Proxies
Step 3: Modify Services container/Startup.cs (Configure services) DBContext to include the option .UseLasyLoadingProxies
So your old code might look like :
services.AddDbContext(options =>
services.AddDbContext(options =>
options.UseSqlServer(Configuration.GetConnectionString("LocalConnection"))
now it might look like this :
services.AddDbContext<ApplicationDbContext>(options =>
options.UseSqlServer(Configuration.GetConnectionString("LocalConnection"))
.UseLazyLoadingProxies());
Step 4 - Modify your DBContext Class to lasy load the related entities (Yes they must all be listed which is probably not optimal but im sure MS will address this)
builder.Entity<Image>().HasOne(u => u.ApplicationUser)
.WithMany(i => i.Images)
.HasForeignKey(u => u.ApplicationUserId)
.HasConstraintName
(
"FK_Image_AspNetUsers_ApplicationUserId"
);
builder.Entity<Video>().HasOne(u => u.ApplicationUser)
.WithMany(p => p.Videos)
.HasForeignKey(u => u.ApplicationUserId)
.HasConstraintName
(
"FK_Video_AspNetUsers_ApplicationUserId"
);
builder.Entity<Audio>().HasOne(u => u.ApplicationUser)
.WithMany(p => p.Audios)
.HasForeignKey(u => u.ApplicationUserId)
.HasConstraintName
(
"FK_Audio_AspNetUsers_ApplicationUserId"
);
you'll notice that im using Identity Core - in the table "AspNetUsers" there is no ApplicationUserId column so you must have the foreign key constraint in place which should already be there if you've modified your class appropriately which i will show below:
Step 5 Make sure you're classes look like this -->
ApplicationUser Class
public class ApplicationUser : IdentityUser, ITraits
{
public int Age { get; set; }
public Ethnicity Ethnicity { get; set; }
public Color EyeColor { get; set; }
public Color HairColor { get; set; }
public int Height { get; set; }
public Race Race { get; set; }
public CuckRole CuckRole { get; set; }
public BiologicalSex BiologicalSex { get; set; }
public Sexuality Sexuality { get; set; }
public Color SkinColor { get; set; }
public int Weight { get; set; }
public DateTime BirthDay { get; set; }
public virtual ICollection<Image> Images { get; set; }<--must be virtual
public virtual ICollection<Video> Videos { get; set; }<--must be virtual
public virtual ICollection<Audio> Audios { get; set; }<--must be virtual
public bool Equals(Traits other)
{
throw new NotImplementedException();
}
}
one of the media classes :
Images:
public class Image
{
//Fields and Properties//
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
public string Name { get; set; }
public string Path { get; set; }
public virtual ApplicationUser ApplicationUser { get; set; }<-be virtual
public virtual string ApplicationUserId { get; set; }<--must be virtual
public Image()
{
}
public Image(string path) => Path = path;
}
Step 6
in a view all you need to do is have a ApplicationUser and you can pull the current user using the httpcontext like so :
in your controller preferably although you can do this in the view
ApplicationUser user = await _usermanager.GetUserAsync(HttpContext.User);
then pass the user to the view as
return View(user)
Step 7
in your view make user the model is applicationuser
somewhere in your view try and access the media classes via the user object so
foreach (Audio clip in Model.Clips)
{
<img src="#clip.path" />
}
viola !
**Edit just a helpful read about the topic and proxies etc - ef core 2-1 whats new with lazy loading
In your DbContext-class you can override the OnModelCreating method and configure your relations here.
There are some cleaner ways, but this might be good start.
protected override void OnModelCreationg(DbModelBuilder modelBuilder)
{
// on-to-many relation example
modelBuilder.Entity<Audio>()
.HasOptional(audio => audio.Owner)
.WithMany(owner => owner.Clips)
.HasForeignKey(audio => audio.OwnerId) // this one is missing in your example
.WillCascadeOnDelete(false); // maybe true? depending on what should happen if the user gets deleted
}
You need to tell EF how to manage your relations - you will need a foreign key (Audio.OwnerId).
Another key-word for further investigations might by be ObjectEntityConfiguration.
Forewarning: I know approximately nothing when it comes to MVC/Entity Framework/Linq queries.
I'm having an issue when I try to query the database. Here's the query I'm using:
int? UserId = db.StudentModel
.Where(c => c.UserName == certUserName)
.Select(c => c.UserId)
.FirstOrDefault();
When it searches the database, it successfully retrieves the UserId.
The problem is that I then use the following query:
CompletionsModel student = db.Completions.Find(UserId);
When I do this, it throws an inner exception that states
{"Invalid column name 'UserProfile_UserId'."}
The weird thing is that when I go to my code and mouse over the 'db' part of the command to see what data it's holding, it has CourseModel, StudentModel, and Completions (though the model's actual filename is CompletionsModel - is that a clue?), so it seems like they're linked properly.
Here's the code for my three models and the database context.
CompletionsModel (UserProfile is white text in my code; not sure why it's teal here Same with UserId and CompletionDate):
[Table("Completion")]
public class CompletionsModel
{
[Key]
public int UserId { get; set; }
public string PRD_NUM { get; set; }
public DateTime CompletionDate { get; set; }
public virtual CourseModel PRD { get; set; }
public virtual StudentModel UserProfile { get; set; }
}
CourseModel:
[Table("PRD")]
public class CourseModel
{
[Key]
public string PRD_NUM { get; set; }
public string PRD_TIT { get; set; }
//because any number of students can be enrolled in one course
public virtual ICollection<CompletionsModel> CompletionsModel { get; set; }
}
StudentModel:
[Table("UserProfile")]
public class StudentModel
{
[Key]
public int UserId { get; set; }
public string UserName { get; set; }
public virtual ICollection<CompletionsModel> CompletionsModel { get; set; }
}
DBContext:
public class ClassContext : DbContext
{
public ClassContext()
: base("DefaultConnection")
{
}
public DbSet<StudentModel> StudentModel { get; set; }
public DbSet<CompletionsModel> Completions { get; set; }
public DbSet<CourseModel> CourseModel { get; set; }
}
And finally, an image of my database layout - maybe this will help things along, too:
I'm too at the beginning of Entity Framework, but what does irritate me is, that you have kind of foreign key relationship between Completion and UserProfile, without really defining, a int column as foreign key in your Completion Table.
You could try to change
public virtual StudentModel UserProfile { get; set; }
to something like
public virtual int StudentId { get; set; }
[ForeignKey("StudentId")]
public virtual StudentModel UserProfile { get; set; }
The same for PRD
But maybe a change in your database is not what you want.
What you could also do, is to remove these lines
public virtual CourseModel PRD { get; set; }
public virtual StudentModel UserProfile { get; set; }
Hope that helps.
EDIT:
I guess the problem is, that you are missing the ForeignKey Attribute at your UserProfile property in your Completions table.
So use
[ForeignKey("UserId")]
public virtual StudentModel UserProfile { get; set; }
instead of
public virtual StudentModel UserProfile { get; set; }
if the UserIds are representing the same user