添加一列以联接表EF6

Question

I'm working with EF6 code first with database migrations and I'm a beginner. I'm building a web api. In my model plan I have a User (Identity Framework) and a Location class with a many to many relationship. EF6 automatic created a table LocationUser but I want to extend this table with some extra columns. But what is the best way to do that.

Of course I've searched for some solutions but I'm not sure what is the best way to go.

I can edit the last migration Up method and add the columns I want but I'm not sure if this is the best way. In my opinion creating a new model class manually is also a possibility.

Could anyone tell me what is the best way and elaborate why?

User.cs

public class User : IdentityUser
{
    public virtual ICollection<Location> Locations { get; set; }
    // Other code for Identity Framework
}

Location.cs

public class Location
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
    public double Lat { get; set; }
    public double Lng { get; set; }

    public virtual ICollection<User> Users{ get; set; }
}

Answer 1

The best way in my opinion is to use fluet api in its context follows a tutorial for better understanding:

Sample:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{

    modelBuilder.Entity<User>()
                .HasMany<Location>(u => u.Locations)
                .WithMany(l => l.Students)
                .Map(ul =>
                        {
                            cs.MapLeftKey("UserId");
                            cs.MapRightKey("LocationId");
                            cs.ToTable("UserLocation");
                        });

}

Tutorial: http://www.entityframeworktutorial.net/code-first/configure-many-to-many-relationship-in-code-first.aspx

For updates to the model I always create new migrations so as not to compromise the actual history of actions.

Answer 2

You can create your own UserLocation class like below.

public class UserLocation
{
    public int Id { get; set; }
    public Location Location { get; set; }
    public User User { get; set; }
    //Extra fields you want can go here
}

Then in your User and Location classes you would change the link to use your UserLocation class.

Example:

public class User : IdentityUser
{
    public virtual ICollection<UserLocation> Locations { get; set; }
    // Other code for Identity Framework
}

Can also add EntityTypeConfigurations to your classes to enforce the many-many, below would be the one for User

public class UserConfiguration : EntityTypeConfiguration<User>
{
    public UserConfiguration()
    {
        HasKey(x => x.Id);
        HasMany(x => x.Locations);
    }
}