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Foreign key Entity Framework - code first migrations

I have a problem with my entities. I'm using EF code-first migrations and the migrations are failing with this error:
Introducing FOREIGN KEY constraint 'FK_OrdersChildsProducts_Orders_OrderId' on table 'OrdersChildsProducts' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints.
Here's my PersonJceProfile entity :
[Table("PersonJceProfiles")]
public class PersonJceProfile : BaseEntity
{
[ForeignKey("Ces")]
public int? CeId { get; set; }
public ICollection<Child> Children { get; set; }
public Order Order { get; set; }
public PersonJceProfile()
{
Children = new List<Child>();
}
}
Here's my Order entity :
[Table("Orders")]
public class Order : BaseEntity
{
[Key]
public int Id { get; set; }
//ForeignKey
[Required]
[ForeignKey("PersonJceProfiles")]
public int PersonJceProfileId { get; set; }
[Required]
public int OrderStatus { get; set; }
[Required]
public bool IsSecurePayment { get; set; }
public int LeftToPayPersonOrder { get; set; }
public string Delivery { get; set; }
public ICollection<OrderChildProduct> OrderChildProduct { get; set; }
public Order()
{
OrderChildProduct = new Collection<OrderChildProduct>();
}
}
Here's my Child entity :
[Table("Childrens")]
public class Child :BaseEntity
{
[Key]
public int Id { get; set; }
[Required]
public string FirstName { get; set; }
[Required]
public string LastName { get; set; }
[Required]
public DateTime? BirthDate { get; set; }
[Required]
public string Gender { get; set; }
public bool? IsActif { get; set; }
public decimal AmountParticipationCe { get; set; }
public bool? IsRegrouper { get; set; }
[Required]
[ForeignKey("PersonJceProfiles")]
public int PersonJceProfileId { get; set; }
}
Here's my Product Entity
public class Product : Good
{
public string File { get; set; }
public bool? IsDisplayedOnJCE { get; set; }
public bool? IsBasicProduct { get; set; }
public int? PintelSheetId { get; set; }
public int OriginId { get; set; }
[Required]
[ForeignKey("Suppliers")]
public int SupplierId { get; set; }
}
Here's my OrderChildProduct entity :
[Table("OrdersChildsProducts")]
public class OrderChildProduct
{
public int OrderId { get; set; }
public int ChildId { get; set; }
public int ProductId { get; set; }
public int LeftToPayChildOrder { get; set; }
public Order Order { get; set; }
public Child Child { get; set; }
public Product Product { get; set; }
}
Here's my context :
modelBuilder.Entity<OrderChildProduct>().HasKey(ccp => new { ccp.OrderId, ccp.ChildId, ccp.ProductId });
I suppose i do destro a relationship like this :
modelBuilder.Entity<Entity>()
.HasRequired(c => c.ForeignKey)
.WithMany()
.WillCascadeOnDelete(false);
but I can't see between which. Because
When I delete PersonJceProfiles : Order must be deleted - OrderChildProduct must be deleted - Child must be deleted
When I delete Order : OrderChildProduct must be deleted
When I delete Order childProduct : nothing must be deleted expect himself
What am I doing wrong? Thanks

The error is self described. You must configure the relationships in the OrderChildProduct table like:
entity.HasOne(p => p.Order)
.WithMany(p => p.OrderChildProduct)
.HasForeignKey(p => p.OrderId)
.OnDelete(Microsoft.EntityFrameworkCore.Metadata.DeleteBehavior.Restrict);
You can use either Restrict or Cascade depending on your requirements.
Also the other 2 relationships must be defined as well.
This is not an error. This is more like a warning... the way EF tells you that it doesn't fully understand the relationships and you must configure them manually.

EF Core self referencing many to many

I have User table and I'd like to add connection called UserFriend between 2 users. I've searched a lot and basicly tried many different solutions and none of them worked. Everytime I get same error:
Introducing FOREIGN KEY constraint 'FK_UserFriends_Users_Friend2Id' on table 'UserFriends' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints.
Here are my models:
public class User
{
[Key]
public Guid Id { get; set; }
public string Username { get; set; }
public string EmailAddress { get; set; }
public string Firstname { get; set; }
public string Lastname { get; set; }
public virtual ICollection<UserFriend> Friends { get; set; }
public virtual ICollection<UserFriend> FriendOf { get; set; }
}
public class UserFriend
{
public User Friend1 { get; set; }
public Guid Friend1Id { get; set; }
public User Friend2 { get; set; }
public Guid Friend2Id { get; set; }
public bool Confirmed { get; set; }
public DateTime Added { get; set; }
}
And here's code in DataContext:
modelBuilder.Entity<UserFriend>().HasKey(sc => new { sc.Friend1Id, sc.Friend2Id });
modelBuilder.Entity<UserFriend>()
.HasOne(c => c.Friend1)
.WithMany(c => c.FriendOf)
.HasForeignKey(f => f.Friend1Id);
modelBuilder.Entity<UserFriend>()
.HasOne(c => c.Friend2)
.WithMany(c => c.Friends)
.HasForeignKey(f => f.Friend2Id)
.OnDelete(DeleteBehavior.Restrict);

Change your code to below and remove the other lines you have posted.
public class User
{
[Key]
public Guid Id { get; set; }
public string Username { get; set; }
public string EmailAddress { get; set; }
public string Firstname { get; set; }
public string Lastname { get; set; }
public virtual ICollection<UserFriend> Friends { get; set; }
public virtual ICollection<UserFriend> FriendOf { get; set; }
}
public class UserFriend
{
public User Friend1 { get; set; }
[ForeignKey("Friend1")]
public Guid? Friend1Id { get; set; }
public User Friend2 { get; set; }
[ForeignKey("Friend2")]
public Guid? Friend2Id { get; set; }
public bool Confirmed { get; set; }
public DateTime Added { get; set; }
}
modelBuilder.Entity<User>();
modelBuilder.Entity<UserFriend>();

How to create a third table for Many to Many relationship in Entity Framework Core?

I have two classes:
One is User
public class User
{
public int Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string Email { get; set; }
public List<Subscription> Subscriptions { get; set; }
}
Other is Subscription:
public class Subscription
{
public int Id { get; set; }
public string Name { get; set; }
public decimal Price { get; set; }
}
As you can see that User has a list of Subscriptions.
Now when using the entity framework code first approach I am getting a table for User which doesn't contain Subscriptions but a new column for User Id is being added to Subscription table. I was expecting to have a third table which contains two columns one with User ID and the other with subscription ID.
How can I achieve this?

From documentation:
Many-to-many relationships without an entity class to represent the join table are not yet supported. However, you can represent a many-to-many relationship by including an entity class for the join table and mapping two separate one-to-many relationships.
So this answer is correct.
I just corrected code a little bit:
class MyContext : DbContext
{
public DbSet<Use> Users { get; set; }
public DbSet<Subscription> Subscriptions { get; set; }
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<UserSubscription>()
.HasKey(t => new { t.UserId, t.SubscriptionId });
modelBuilder.Entity<UserSubscription>()
.HasOne(pt => pt.User)
.WithMany(p => p.UserSubscription)
.HasForeignKey(pt => pt.UserId);
modelBuilder.Entity<UserSubscription>()
.HasOne(pt => pt.Subscription)
.WithMany(t => t.UserSubscription)
.HasForeignKey(pt => pt.SubscriptionId);
}
}
public class User
{
public int Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string Email { get; set; }
public List<UserSubscription> UserSubscriptions{ get; set; }
}
public class Subscription
{
public int Id { get; set; }
public string Name { get; set; }
public decimal Price { get; set; }
public List<UserSubscription> UserSubscriptions{ get; set; }
}
public class UserSubscription
{
public int UserId { get; set; }
public User User { get; set; }
public int SubscriptionId { get; set; }
public Subscription Subscription { get; set; }
}
PS. You don't need use virtual in navigation property, because lazy loading still not available in EF Core.

Create a third middle table named: UserSubscriptions for example.
public class User
{
public int ID { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string Email { get; set; }
public virtual ICollection<UserSubscription> Subscriptions { get; set; }
}
public class Subscription
{
public int ID { get; set; }
public string Name { get; set; }
public decimal Price { get; set; }
}
public class UserSubscription
{
public int ID { get; set; }
public int SubscriptionID { get; set; }
public decimal Price { get; set; }
public int UserID { get; set; }
public virtual User { get; set; }
public DateTime BeginDate { get; set; }
public DateTime EndDate { get; set; }
}
Second Solution:
Add reference for Subscription to User and name it CurrentSubscription for example.
public class User
{
public int ID { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string Email { get; set; }
public int CurrentSubscriptionID { get; set; }
public virtual Subscription Subscription { get; set; }
}
public class Subscription
{
public int ID { get; set; }
public string Name { get; set; }
public decimal Price { get; set; }
}

How can I configure many-to-many relationship to my own created entity in entity framework

I have some classes:
public class Values : Entity
{
[Key]
public int Values_ID { get; set; }
[Required]
public string Values_Name { get; set; }
[Required]
public int ValuesNumeric { get; set; }
public virtual ICollection<ValuesMetrics> ValuesMetrics { get; set; }
}
public class GQMetric : Entity
{
[Key]
public int GQMetric_ID { get; set; }
[Required]
public string GQMetricName { get; set; }
[Required]
public int Importance_ID { get; set; }
public virtual List<GQMetricsQuestions> GQMetricsQuestions { get; set; }
public virtual ICollection<ValuesMetrics> ValuesMetrics { get; set; }
public virtual ImportanceScale ImportanceScale { get; set; }
}
I need to create many-to-many relationship to my own created class ValuesMetrics, not to automatically generated table by entity framework. I have tried a lot of solutions here, here and here but none of it did not work. Eventually, I did this:
public class ValuesMetrics : Entity
{
public int GQMetric_ID { get; set; }
public int Value_ID { get; set; }
public virtual GQMetric GQMetric { get; set; }
public virtual Values Values { get; set; }
}
FluentAPI:
modelBuilder.Entity<ValuesMetrics>()
.HasKey(c => new { c.GQMetric_ID, c.Value_ID });
modelBuilder.Entity<GQMetricsQuestions>()
.HasKey(c => new { c.GQMetric_ID, c.Question_ID });
but created table (ValuesMetrics) have an excessive relationship (GQMetrics_GQMetric_ID). I need only two primary keys from Values and GQMetrics tables
Can you advice me how to solve this problem? Thanks for any help!

Applied #Esteban 's solution from the link already referenced by you: Create code first, many to many, with additional fields in association table
Basically I did the following three changes:
Used POCO entities instead of inheriting from Entity class
Removed EF attributes, since we'll be using fluent API anyway
Changed fluent API configuration
Resulting code:
public class MyContext : DbContext
{
public DbSet<Values> Values { get; set; }
public DbSet<GQMetric> GqMetric { get; set; }
public DbSet<ValuesMetrics> ValuesMetrics { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Values>().HasKey(values => values.Values_ID);
modelBuilder.Entity<GQMetric>().HasKey(metric => metric.GQMetric_ID);
modelBuilder
.Entity<ValuesMetrics>()
.HasKey(valuesMetrics => new
{
valuesMetrics.Value_ID,
valuesMetrics.GQMetric_ID
});
modelBuilder
.Entity<ValuesMetrics>()
.HasRequired(valuesMetrics => valuesMetrics.Values)
.WithMany(valueMetrics => valueMetrics.ValuesMetrics)
.HasForeignKey(valueMetrics => valueMetrics.Value_ID);
modelBuilder
.Entity<ValuesMetrics>()
.HasRequired(valuesMetrics => valuesMetrics.GQMetric)
.WithMany(valueMetrics => valueMetrics.ValuesMetrics)
.HasForeignKey(valueMetrics => valueMetrics.GQMetric_ID);
base.OnModelCreating(modelBuilder);
}
}
public class Values
{
public int Values_ID { get; set; }
public string Values_Name { get; set; }
public int ValuesNumeric { get; set; }
public virtual ICollection<ValuesMetrics> ValuesMetrics { get; set; }
}
public class GQMetric
{
public int GQMetric_ID { get; set; }
public string GQMetricName { get; set; }
public virtual ICollection<ValuesMetrics> ValuesMetrics { get; set; }
}
public class ValuesMetrics
{
public int GQMetric_ID { get; set; }
public int Value_ID { get; set; }
public virtual GQMetric GQMetric { get; set; }
public virtual Values Values { get; set; }
}

Table Splitting Entity Framework Code First - 3+ Entities

I've posted a question in Programmers: https://softwareengineering.stackexchange.com/questions/315857/entity-framework-code-first-c-class-separation-and-eav
One solution to the problem is Table Splitting in Entity Framework. So far, I've seen how to do this with 2 entities, but not with 3 or more.
Here are the models I want to share a same table with:
[Table("Tournament")]
public partial class PGTournament : IImageable
{
public int Id { get; set; }
public string Name { get; set; }
public GameGenre GameGenre { get; set; }
public TournamentFormat TournamentFormat { get; set; }
public TournamentStatus Status { get; set; }
public string Description { get; set; }
public virtual List<PrizePool> Prizes { get; set; }
public DateTime StartDate { get; set; }
public DateTime EndDate { get; set; }
public virtual List<Participants.Participant> Participants { get; set; }
public decimal Cost { get; set; }
public string Streaming { get; set; }
public int? ChallongeTournamentId { get; set; }
public string Bracket { get; set; }
public virtual List<TournamentMatch> Matches { get; set; }
public int MainImageId { get; set; }
public virtual Media MainImage { get; set; }
public bool IsFollowUp { get; set; }
public int? FollowUpTournamentId { get; set; }
[ForeignKey("FollowUpTournamentId")]
public virtual PGTournament FollowUptournament { get; set; }
public int MediaID { get; set; }
public int MainImageID { get; set; }
//Properties that share same table:
public virtual TournamentOrganizer Organizer { get; set; } //Change to Organizer
public virtual TournamentOrganizerSetting OrganizerSetting { get; set; }
public virtual TournamentSettings TournamentSettings { get; set; }
public virtual TournamentRules Rules { get; set; }
}
All the properties you see that are virtual and don't have a List<> as their type, I want them to share a same table (If it is possible).
[Table("Tournament")]
public partial class TournamentOrganizer
{
public int Id { get; set; }
public string Name { get; set; }
public string UserId { get; set; }
[ForeignKey("UserId")]
public AppUser User { get; set; }
public int LogoId { get; set; }
[ForeignKey("LogoId")]
public Media Logo { get; set; }
public virtual TournamentOrganizerSetting Settings { get; set; }
public virtual TournamentRules Rules { get; set; }
public virtual TournamentSettings TournamentSettings { get; set; }
public virtual PGTournament Tournament { get; set; }
}
[Table("Tournament")]
public partial class TournamentSettings
{
public int Id { get; set; }
public string Address { get; set; }
public string LocationGoogleMaps { get; set; }
public bool isOnline { get; set; }
public int MaxPlayers { get; set; }
public List<TournamentAssistant> TournamentAssistants { get; set; }
public virtual TournamentOrganizer Organizer { get; set; } //Change to Organizer
public virtual TournamentRules Rules { get; set; }
public virtual TournamentOrganizerSetting OrganizerSettings { get; set; }
public virtual PGTournament Tournament { get; set; }
}
[Table("Tournament")]
public partial class TournamentOrganizerSetting
{
public int Id { get; set; }
public string Location { get; set; }
//Properties that share same table:
public virtual TournamentOrganizer Organizer { get; set; } //Change to Organizer
public virtual TournamentRules Rules { get; set; }
public virtual TournamentSettings TournamentSettings { get; set; }
public virtual PGTournament Tournament { get; set; }
}
[Table("Tournament")]
public partial class TournamentRules
{
public int Id { get; set; }
public string Bans { get; set; }
public string Allowed { get; set; }
public string Description { get; set; }
public string FileName { get; set; }
public string FilePath { get; set; }
//Properties that share same table:
public virtual TournamentOrganizer Organizer { get; set; } //Change to Organizer
public virtual TournamentOrganizerSetting OrganizerSetting { get; set; }
public virtual TournamentSettings TournamentSettings { get; set; }
public virtual PGTournament Tournament { get; set; }
}
I don't know why the classes are partial. I've been following several tutorials over the Internet, such as this: http://www.c-sharpcorner.com/UploadFile/ff2f08/table-splitting-in-entity-framework-6-code-first-approach/
I can't get them to work.
I have even tried this in the DbModelBuilder:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<PGTournament>().ToTable("Tournament");
modelBuilder.Entity<PGTournament>()
.HasKey(e => e.Id)
.HasOptional(e => e.FollowUptournament)
.WithMany();
modelBuilder.Entity<PGTournament>()
.HasKey(e => e.Id)
.HasRequired(e => e.Organizer)
.WithRequiredDependent(e => e.Organizer)
modelBuilder.Entity<TournamentOrganizer>()
.HasKey(e => e.Id)
.HasRequired(e => e.Settings)
.WithRequiredDependent(e => e.Organizer);
modelBuilder.Entity<TournamentViewModel>()
.HasKey(e => e.Id)
.HasRequired(e => e.Settings)
.WithRequiredDependent(e => e.Organizer);
modelBuilder.Entity<TournamentOrganizer>().Map(m => m.ToTable("Tournament"));
modelBuilder.Entity<TournamentOrganizerSetting>().Map(m => m.ToTable("Tournament"));
base.OnModelCreating(modelBuilder);
}
There doesn't seem to be a StackOverflow post with Mapping to 3 or more entities.
When I try to run it, this is the error I get:
One or more validation errors were detected during model generation:
Pro_Gaming.Infrastructure.IdentityUserLogin: : EntityType 'IdentityUserLogin' has no key defined. Define the key for this EntityType.
Pro_Gaming.Infrastructure.IdentityUserRole: : EntityType 'IdentityUserRole' has no key defined. Define the key for this EntityType.
IdentityUserLogins: EntityType: EntitySet 'IdentityUserLogins' is based on type 'IdentityUserLogin' that has no keys defined.
IdentityUserRoles: EntityType: EntitySet 'IdentityUserRoles' is based on type 'IdentityUserRole' that has no keys defined.

This answer comes from Cole Wu from ASP.NET forums:
http://forums.asp.net/p/2093110/6043922.aspx?p=True&t=635968548324560382
The answer is the following:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
//Do not delete this:
base.OnModelCreating(modelBuilder);
modelBuilder.Entity<Tournament>()
.HasKey(e => e.TournamentId)
.HasRequired(e => e.Rules)
.WithRequiredPrincipal();
modelBuilder.Entity<Tournament>()
.HasKey(e => e.TournamentId)
.HasRequired(e => e.TournamentSettings)
.WithRequiredDependent();
modelBuilder.Entity<TournamentOrganizer>()
.HasKey(e => e.Id)
.HasRequired(e => e.Settings)
.WithRequiredDependent();
modelBuilder.Entity<Tournament>().ToTable("Tournament");
modelBuilder.Entity<TournamentRules>().ToTable("Tournament");
modelBuilder.Entity<TournamentSettings>().ToTable("Tournament");
modelBuilder.Entity<TournamentOrganizer>().ToTable("TournamentOrganizer");
modelBuilder.Entity<TournamentOrganizerSetting>().ToTable("TournamentOrganizer");
}
Explaining a bit:
There is no need for partial classes (I say this because there is an
example that states that you need partial classes, this is not
true):
I haven't tested this, but I used the same key for all the classes that I wanted to share the same table.
modelBuilder.Entity <= TheEntity will be the main class you want everything mapped to.
If you are using ASP.NET Identity and you are extending from IdentityDbContext (which is my case), It is very important
to include base.OnModelCreating(modelBuilder) in the OnModelCreating method, otherwise you'll be hit with Identityissues that it doesn't find the primary key for IdenittyUser.
You would then use:
modelBuilder.Entity.ToTable("MyTable")
modelBuilder.Entity.ToTable("MyTable")
modelBuilder.Entity.ToTable("MyTable")
This will map Entity1, Entity2, Entity3, etc to MyTable.