Question

I have a parent/child database relationship between the table ACCOUNT and the table USER. Currently I have mapped a bi-directional Fluent mappings like this:

public class Account {
  public virtual IList<User> ListUsers { get; private set; }

  public virtual void AddUser(User user)
  {
    user.Account = this;
    ListUsers.Add(user);
  }
}

MAPPING: HasMany(x => x.ListUsers).Table("UserInfo").KeyColumn("Id_Account").Inverse().Cascade.All().AsList();

public class User {
  public virtual Account Account { get; set; }
  public string Username { get; set; } 
}

MAPPING: References(x => x.Account).Column("Id_Account");

In practice I cannot foresee that I will ever want to reference the Account entity from the User entity. Likewise I cannot foresee my wanting to load all of the User entities from the parent Accounts entity. I am fairly new to NHibernate and was wondering is the above method still the best way to go performance wise? Is a bi-directional relationship preferred and should I look to referencing the Id only? Thanks

Answer 1

1. bi-directional references is the correct approach, in my opinion. If you use lazy-loading on the Account property, then it would only load the account’s id anyway.
2. you specified that the ListUsers property is inverse=true, meaning the User entity is responsible for saving the reference. Therefore, I believe (if I remember correctly) that the line ListUsers.Add(user); is not necessary, since the association will be created by the User entity.
   So this means that you don’t have to load the entire ListUsers collection from the db when you add a user.