I'm traying to do a mapping with One to One relationship with id as "foreign", I can't change the database
Those are the tables
Cutomer
int CustomerId
string Name
CustomerDetail
int CustomerId
string Details
Entity Splittitng does not works for me since i need a left outter join.
Any Ideas?
Thanks in advance,
and sorry about my english.
You can use the Shared Primary Key mapping here.
public class Customer
{
public int CustomerId { get; set; }
public string Name { get; set; }
public virtual CustomerDetail CustomerDetail { get; set; }
}
public class CustomerDetail
{
public int CustomerId { get; set; }
public string Details { get; set; }
public virtual Customer Customer { get; set; }
}
public class MyContext : DbContext
{
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<CustomerDetail>().HasKey(d => d.CustomerId);
modelBuilder.Entity<Customer>().HasOptional(c => c.CustomerDetail)
.WithRequired(d => d.Customer);
}
}
Related
I have a similar problem to the one posted here:
Entity Framework Code First - two Foreign Keys from same table, however it's very old and doesn't apply to Core and I can't get the suggestions to work for me.
Basically, I'm trying to create a fixture table which will have two foreign keys to the team table. A fixture is made up of a home team and an away team. Having nullable fields isn't an option.
Consider a fixture, with two teams.
public class Fixture
{
public int Id { get; set; }
public Team HomeTeam { get; set; }
public int HomeTeamId { get; set; }
public Team AwayTeam { get; set; }
public int AwayTeamId { get; set; }
public virtual Team HomeTeam { get; set; }
public virtual Team AwayTeam { get; set; }
}
public class Team
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
public String Name { get; set; }
public ICollection<Fixture> HomeFixtures { get; set; } = new List<Fixture>();
public ICollection<Fixture> AwayFixtures { get; set; } = new List<Fixture>();
}
I get the error...
Unable to determine the relationship represented by navigation property 'Fixture.HomeTeam' of type 'Team'. Either manually configure the relationship, or ignore this property using the '[NotMapped]' attribute or by using 'EntityTypeBuilder.Ignore' in 'OnModelCreating'.
So I tried to add some OnModelCreating code in the database context:
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<Fixture>()
.HasOne(m => m.HomeTeam)
.WithMany(t => t.HomeFixtures)
.HasForeignKey(m => m.HomeTeamId)
.OnDelete(DeleteBehavior.Restrict);
modelBuilder.Entity<Fixture>()
.HasOne(m => m.AwayTeam)
.WithMany(t => t.AwayFixtures)
.HasForeignKey(m => m.AwayTeamId)
.OnDelete(DeleteBehavior.Restrict);
}
Then I got the error:
Introducing FOREIGN KEY constraint 'FK_Fixtures_Teams_HomeTeamId' on table 'Fixtures' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints.
Can anyone help with getting this setup please?
Thanks.
public class Fixture
{
public int Id { get; set; }
public int HomeTeamId { get; set; }
public int AwayTeamId { get; set; }
[ForeignKey("HomeTeamId")]
public virtual Team HomeTeam { get; set; }
[ForeignKey("AwayTeamId")]
public virtual Team AwayTeam { get; set; }
}
This way navigation will work. Also as suggested by #Ivan remove duplicate getters and setters.
Solution below worked for me for EF Core 3:
Make sure to make foreign keys nullable
Specify default behavior on Delete
public class Match
{
public int? HomeTeamId { get; set; }
public int? GuestTeamId { get; set; }
public float HomePoints { get; set; }
public float GuestPoints { get; set; }
public DateTime Date { get; set; }
public Team HomeTeam { get; set; }
public Team GuestTeam { get; set; }
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<Match>()
.HasRequired(m => m.HomeTeam)
.WithMany(t => t.HomeMatches)
.HasForeignKey(m => m.HomeTeamId)
.OnDelete(DeleteBehavior.ClientSetNull);
modelBuilder.Entity<Match>()
.HasRequired(m => m.GuestTeam)
.WithMany(t => t.AwayMatches)
.HasForeignKey(m => m.GuestTeamId)
.OnDelete(DeleteBehavior.ClientSetNull);
}
IQueryable<Product> product = objContext.Set<Product>().Include(p =>
p.Categories.Name).Where(p => p.Id == 2);
As per the current view, I'm getting an error. It says add other model with their properties. i.e. to include Category model and corresponding Name property.
#model IEnumerable<>crudOneToMany.Models.Product>
using viewmodel, is it possible to join two tables?
View
Error
A specified Include path is not valid. The EntityType 'crudOneToMany.Models.Category' does not declare a navigation property with the name 'Name'.
public class Product
{
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public int CategoryId { get; set; }
public virtual Category Categories { get; set; }
}
public class Category
{
public int Id { get; set; }
public string Name { get; set; }
public ICollection<Product> Products { get; set; }
}
public class ProductDBContext : DbContext
{
public ProductDBContext()
: base("ProductDBContext")
{
}
public DbSet<Product> Products { get; set; }
public DbSet<Category> Categories { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Product>().HasRequired(o => o.Categories).WithMany(o => o.Products).HasForeignKey(o => o.CategoryId);
base.OnModelCreating(modelBuilder);
}
}
Your problem is here:
.Include(p => p.Categories.Name)
Instead you should write .Include(p => p.Categories)
This means that in output there will be loaded Categories navigation collection to product.
Name is simple string property (is not navigation property so it should not be included)
Here is the proposed ViewModel for you.
ProductViewModel.cs
public class ProductViewModel
{
public int Id { get; set; }
[Required(ErrorMessage = "required")]
public string ProductName { get; set; }
public Category Category { get; set; }
public ICollection<Category> Categories { get; set; }
}
I have those 2 Models
public class BranchEmployees
{
public int ID { get; set; }
[Required, Column(Order = 0), Key]
public string ApplicationUserID { get; set; }
[Required, Column(Order = 1), Key]
public int BranchID { get; set; }
public virtual ICollection<ApplicationUser> ApplicationUser { get; set; }
public virtual ICollection<Branch> Branch { get; set; }
}
public class Branch
{
public int ID { get; set; }
public string BranchName { get; set; }
[Required]
public string ApplicationUserID { get; set; }
public ApplicationUser User { get; set; }
public virtual ICollection<BranchEmployees> BranchEmployees { get; set; }
}
public class ApplicationUser
{
//rest of the code
}
UPDATE
I have everything set up but what I want is the query that gets me the Employees whose IDs are in the branch employees table
, I'm using entity framework code first with MVC 5 , how do I do it ?
Assuming that your ApplicationUser class will have a navigational property called BranchEmployees, here is the query that gets me the Employees whose IDs are in the branch employees table
List<ApplicationUsers> employeeNames =
dbContext
.ApplicationUsers
.Where(au => au.BranchEmployees
.Count() > 0).ToList();
Also, can you provide whole model including ApplicationUser? I also wonder why you do not prefer BranchEmployees to inherit from ApplicationUser.
You don't need a class that indicates a many-to-many relation between two tables when you do code-first. The key here is to create virtual properties of those classes. Lets say you have a class Student and class Course. Students can be in many Courses and Courses can have many Students. To generate a database using these models the classes should look like this:
public class Student
{
private ICollection<Course> _courses;
public Student()
{
this._courses = new HashSet<Course>();
}
[Key]
public int Id { get; set; }
public string FullName { get; set; }
public virtual ICollection<Course> Courses
{
get { return this._courses; }
set { this._courses = value; }
}
}
And for Course:
public class Course
{
private ICollection<Student> _students;
public Course()
{
this._students = new HashSet<Student>();
}
[Key]
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public virtual ICollection<Student> Students
{
get { return this._students; }
set { this._students = value; }
}
}
I hope that this can help you solve your issue.
I have two entities in my MVC application and I populated the database with Entity Framework 6 Code First approach. There are two city id in the Student entity; one of them for BirthCity, the other for WorkingCity. When I define the foreign keys as above an extra column is created named City_ID in the Student table after migration. Id there a mistake or how to define these FKs? Thanks in advance.
Student:
public class Student
{
public int ID { get; set; }
public string Name { get; set; }
public string Surname { get; set; }
public int BirthCityID { get; set; }
public int LivingCityID { get; set; }
[ForeignKey("BirthCityID")]
public virtual City BirthCity { get; set; }
[ForeignKey("LivingCityID")]
public virtual City LivingCity { get; set; }
}
City:
public class City
{
public int ID { get; set; }
public string CityName { get; set; }
public virtual ICollection<Student> Students { get; set; }
}
To achieve what you want you need to provide some aditional configuration.Code First convention can identify bidirectional relationships, but not when there are
multiple bidirectional relationships between two entities.You can add configuration (using Data Annotations or the Fluent API) to present this
information to the model builder. With Data Annotations, you’ll use an annotation
called InverseProperty. With the Fluent API, you’ll use a combination of the Has/With methods to specify the correct ends of these relationships.
Using Data Annotations could be like this:
public class Student
{
public int ID { get; set; }
public string Name { get; set; }
public string Surname { get; set; }
public int BirthCityID { get; set; }
public int LivingCityID { get; set; }
[ForeignKey("BirthCityID")]
[InverseProperty("Students")]
public virtual City BirthCity { get; set; }
[ForeignKey("LivingCityID")]
public virtual City LivingCity { get; set; }
}
This way you specifying explicitly that you want to relate the BirthCity navigation property with Students navigation property in the other end of the relationship.
Using Fluent Api could be like this:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Student>().HasRequired(m => m.BirthCity)
.WithMany(m => m.Students).HasForeignKey(m=>m.BirthCityId);
modelBuilder.Entity<Student>().HasRequired(m => m.LivingCity)
.WithMany().HasForeignKey(m=>m.LivingCityId);
}
With this last solution you don't need to use any attibute.
Now, the suggestion of #ChristPratt in have a collection of Student in your City class for each relationship is really useful. If you do that, then the configurations using Data Annotations could be this way:
public class Student
{
public int ID { get; set; }
public string Name { get; set; }
public string Surname { get; set; }
public int BirthCityID { get; set; }
public int LivingCityID { get; set; }
[ForeignKey("BirthCityID")]
[InverseProperty("BirthCityStudents")]
public virtual City BirthCity { get; set; }
[ForeignKey("LivingCityID")]
[InverseProperty("LivingCityStudents")]
public virtual City LivingCity { get; set; }
}
Or using Fluent Api following the same idea:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Student>().HasRequired(m => m.BirthCity)
.WithMany(m => m.BirthCityStudents).HasForeignKey(m=>m.BirthCityId);
modelBuilder.Entity<Student>().HasRequired(m => m.LivingCity)
.WithMany(m => m.LivingCityStudents).HasForeignKey(m=>m.LivingCityId);
}
Sheesh. It's been a long day. There's actually a very big, glaring problem with your code, actually, that I completely missed when I commented.
The problem is that you're using a single collection of students on City. What's actually happening here is that EF can't decide which foreign key it should actually map that collection to, so it creates another foreign key specifically to track that relationship. Then, in effect you have no navigation properties for the collections of students derived from BirthCity and LivingCity.
For this, you have to drop down to fluent configuration, as there's no way to configure this properly using just data annotations. You'll also need an additional collection of students so you can track both relationships:
public class City
{
...
public virtual ICollection<Student> BirthCityStudents { get; set; }
public virtual ICollection<Student> LivingCityStudents { get; set; }
}
Then, for Student:
public class Student
{
...
public class StudentMapping : EntityTypeConfiguration<Student>
{
public StudentMapping()
{
HasRequired(m => m.BirthCity).WithMany(m => m.BirthCityStudents);
HasRequired(m => m.LivingCity).WithMany(m => m.LivingCityStudents);
}
}
}
And finally in your context:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Configurations.Add(new Student.StudentMapping());
}
I am using EF4 CTP5. Here are my POCOs:
public class Address
{
public int Id { get; set; }
public string Name { get; set; }
public string Line1 { get; set; }
public string Line2 { get; set; }
public string City { get; set; }
public string State { get; set; }
public string PostalCode { get; set; }
}
public class Customer
{
public int Id { get; set; }
public string Name { get; set; }
public List<Address> Addresses { get; set; }
public List<Order> Orders { get; set; }
}
public class Order
{
public int Id { get; set; }
public decimal Total { get; set; }
public Address ShippingAddress { get; set; }
public Address BillingAddress { get; set; }
}
Is there a way to get Address to be a ComplexType for the Order class? After playing around with this, I'm guessing not, but maybe there's a way I haven't seen.
EDIT: In response to Shawn below, I gave it my best shot:
//modelBuilder.Entity<Order>().Ignore(o => o.BillingAddress);
//modelBuilder.Entity<Order>().Ignore(o => o.ShippingAddress);
modelBuilder.Entity<Order>()
.Property(o => o.BillingAddress.City).HasColumnName("BillingCity");
Fails at runtime with error "The configured property 'BillingAddress' is not a declared property on the entity 'Order'." Trying to use Ignore() doesn't work. Next, the Hanselman article is CTP4, but the CTP5 equivalent is:
modelBuilder.Entity<Order>().Map(mapconfig =>
{
mapconfig.Properties(o => new {
o.Id
, o.Total
, o.BillingAddress.City
});
mapconfig.ToTable("Orders");
});
Fails with error "Property 'BillingAddress.City' of type 'Order' cannot be included in its mapping."
I give up. Maybe the final release will have something like this. Or maybe I need to switch to NHibernate =)
All you need to do is to place ComplexTypeAttribute on Address class:
[ComplexType]
public class Address
{
public int Id { get; set; }
public string Name { get; set; }
public string Line1 { get; set; }
public string Line2 { get; set; }
public string City { get; set; }
public string State { get; set; }
public string PostalCode { get; set; }
}
Alternatively, you can achieve this by fluent API:
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.ComplexType<Address>();
}
But you cannot have Address type as to be both an Entity and a Complex Type, it's one way or another.
Take a look at this blog post where I discuss this at length:
Associations in EF Code First CTP5: Part 1 – Complex Types
If you want Address to be in the same table as Order, you're going to have to tell EF that in the DbContext OnModelCreating override.
Take a look here: http://weblogs.asp.net/scottgu/archive/2010/07/23/entity-framework-4-code-first-custom-database-schema-mapping.aspx