Question

I’ve set up a relational db using MSSQL and I’m trying to use the Entity Framework to talk to it, but I’m having some issues. (This is my first EF project).

I’m able to insert data in both the Machines table and the Contacts table using:

_db.AddToMachines(new Machine { MachineModelId = 0, Owner = "Test", SerialNo = "34242341" });
_db.SaveChanges();

But how can I add Contacts to the Machine?

Answer 1

Your Machines entity should have a navigation property called Contacts and vice versa. Just add the objects to these properties.
Example:

var machine = new Machine { MachineModelId = 0, 
                            Owner = "Test", SerialNo = "34242341" };
var contact = new Contact { ... };
machine.Contacts.Add(contact);

_db.AddToMachines(machine);
_db.SaveChanges();

This should insert a new entry in the Machines table, a new entry in the Contacts table and a new entry in the MachineContacts table referencing the new entries in the two other tables.