CODEWITHSUNDEEP
c#entity-framework-core
Modestas Vacerskas
Modestas Vacerskas

Reputation: 55

c# modelBuilder.Entity

I have these lines of code in the DBcontext class. Can someone explain to me what it does? Does it populate User_roles? But if it does should not it be already inside public DbSet<User_Role> User_Roles. Or does it populate nav properties of Role and user?

 protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<User_Role>()
            .HasOne(x => x.Role)
            .WithMany(y => y.UserRoles)
            .HasForeignKey(x => x.RoleId);

        modelBuilder.Entity<User_Role>()
           .HasOne(x => x.User)
           .WithMany(y => y.UserRoles)
           .HasForeignKey(x => x.UserId);
    }

User class

public class User
{
    public Guid Id { get; set; }
    public string Username { get; set; }
    public string EmailAddress { get; set; }
    public string Password { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    [NotMapped]
    public List<string> Roles { get; set; }

    //nav propery
    public List<User_Role> UserRoles { get; set; }

}

Role class

public class Role
{
    public Guid Id { get; set; }
    public string Name { get; set; }

    //nav property
    public List<User_Role> UserRoles { get; set; }
}

User_role class

public class User_Role
{
    public Guid Id { get; set; }

    public Guid UserId { get; set; }
    public User User { get; set; }

    public Guid RoleId { get; set; }
    public Role Role { get; set; }

}

Upvotes: 1

Views: 1133

Answers (1)

Luke
Luke

Reputation: 1039

It doesn't populate anything in terms of data, assuming that's what you're asking. All that does is configure one-to-many relationships between User_Role and Role, and User_Role and User. This will create your FK constraints in the database when you run migrations and configures your navigation properties.

Recommended reading here: https://learn.microsoft.com/en-us/ef/core/modeling/relationships?tabs=fluent-api%2Cfluent-api-simple-key%2Csimple-key

Upvotes: 3

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