public class User
    {
        #region Property

        public int UserId { get; set; }
        
        [Display(Name = nameof(UserMobile), ResourceType = typeof(ResLabel))]
        public string UserMobile { get; set; }

        [Display(Name = nameof(UserPassword), ResourceType = typeof(ResLabel))]
        public string UserPassword { get; set; }

        #endregion

        #region Relationship

        //User 8->8 Role
        public virtual IList<Role> Roles { get; set; }

        #endregion
    }

 public class Role
    {
        #region Property

        public int RoleId { get; set; }

        [Display(Name = nameof(RoleName), ResourceType = typeof(ResLabel))]
        public string RoleName { get; set; }

        [Display(Name = nameof(RoleDescription), ResourceType = typeof(ResLabel))]
        public string RoleDescription { get; set; }

        #endregion

        #region Relationship

        //Role 8->8 User
        public virtual IList<User> Users { get; set; }

        #endregion

    }

  public class MyContext : DbContext
    {
        #region DbSet

        public virtual DbSet<Role> Roles { get; set; }
            public virtual DbSet<User> Users { get; set; }

        #endregion

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {

            #region Attribute
         
            #region Role

            #region HasKey

            modelBuilder
                .Entity<Role>()
                .HasKey(t => t.RoleId);

            modelBuilder
                .Entity<Role>()
                .Property(t => t.RoleId)
                .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);

            #endregion

            #region HasMaxLength

            modelBuilder
                .Entity<Role>()
                .Property(t => t.RoleName)
                .HasMaxLength(20);

            modelBuilder
                .Entity<Role>()
                .Property(t => t.RoleDescription)
                .HasMaxLength(150);

            #endregion

            #region IsRequired

            modelBuilder
                .Entity<Role>()
                .Property(t => t.RoleName)
                .IsRequired();

            #endregion

            #endregion

            #region User

            #region HasKey

            modelBuilder
                .Entity<User>()
                .HasKey(t => t.UserId);

            modelBuilder
                .Entity<User>()
                .Property(t => t.UserId)
                .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);

            #endregion

            #region HasMaxLength

            modelBuilder
                .Entity<User>()
                .Property(t => t.UserMobile)
                .HasMaxLength(11);

            modelBuilder
                .Entity<User>()
                .Property(t => t.UserPassword)
                .HasMaxLength(50);

            #endregion

            #region IsRequired

            modelBuilder
                .Entity<User>()
                .Property(t => t.UserMobile)
                .IsRequired();

            modelBuilder
                .Entity<User>()
                .Property(t => t.UserPassword)
                .IsRequired();

            #endregion

            #endregion

            #endregion

            #region RelationShip

            #region ManyToMany

            modelBuilder
                           .Entity<User>()
                           .HasMany(p => p.Roles)
                           .WithMany(o => o.Users)
                           .Map(m =>
                           {
                               m.ToTable("UserRole");
                               m.MapLeftKey("UserId");
                               m.MapRightKey("RoleId");
                           });

            modelBuilder.Conventions.Remove<ManyToManyCascadeDeleteConvention>();

            #endregion

            #endregion

            base.OnModelCreating(modelBuilder);
        }