Multiple added entities may have the same primary key in Entity Framework

Question

I am working in a project using EF 4.0.

The Employee table has a column ReferEmployeeID which contains the employee id of the employee that is

Answer 1

Assuming that the EmployeeID in your database table is defined as INT IDENTITY, then you could do this:

// create two new employees - one refers to the other
Employee john = new Employee { EmployeeID = -1, EmpName = "John" };
Employee peter = new Employee { EmployeeID = -2, EmpName = "Peter", ReferEmployeeID = -1 };

// add them to the EF model
ctx.AddToEmployees(john);
ctx.AddToEmployees(peter);

// save changes
ctx.SaveChanges();

So basically, define your new employees with "dummy" EmployeeID values and establish the link (Peter references John here, by means of its "dummy" ID).

When saving this into SQL Server, the Entity Framework will handle the process of getting the real EmployeeID values (which SQL Server hands out when inserting the row) and EF will maintain that link between the two employees.