Entity Framework Code First: How can I create a One-to-Many AND a One-to-One relationship between two tables?
Here is my Model:
public class Customer
{
public int ID { get; set; }
public int MailingAddressID { get; set; }
public virtual Address MailingAddress { get; set; }
public virtual ICollection<Address> Addresses { get; set; }
}
public class Address
{
public int ID { get; set; }
public int CustomerID { get; set; }
public virtual Customer Customer { get; set; }
}
A customer can have any number of addresses, however only one of those addresses can be a mailing address.
I can get the One to One relationship and the One to Many working just fine if I only use one, but when I try and introduce both I get multiple CustomerID keys (CustomerID1, CustomerID2, CustomerID3) on the Addresses table. I'm really tearing my hair out over this one.
In order to map the One to One relationship I am using the method described here http://weblogs.asp.net/manavi/archive/2011/01/23/associations-in-ef-code-first-ctp5-part-3-one-to-one-foreign-key-associations.aspx
Solution 1:
I've struggled with this for almost the entire day and of course I wait to ask here just before finally figuring it out!
In addition to implementing the One to One as demonstrated in that blog, I also then needed to use the fluent api in order to specify the Many to Many since the convention alone wasn't enough with the One to One relationship present.
modelBuilder.Entity<Customer>().HasRequired(x => x.PrimaryMailingAddress)
.WithMany()
.HasForeignKey(x => x.PrimaryMailingAddressID)
.WillCascadeOnDelete(false);
modelBuilder.Entity<Address>()
.HasRequired(x => x.Customer)
.WithMany(x => x.Addresses)
.HasForeignKey(x => x.CustomerID);
And here is the final model in the database:
Solution 2:
I know you're trying to figure out the Entity Framework way of doing this, but if I were designing this I would recommend not even wiring up MailingAddress to the database. Just make it a calculated property like this:
public MailingAddress {
get {
return Addresses.Where(a => a.IsPrimaryMailing).FirstOrDefault();
}
}