DbContext中的一对多映射模型

Question

Currently I am new to MVC and practicing with some demo applications.

I have 2 models.

Employee - (with data members employeeId,name,gender,city,deptId) Department - (with data members id,name,Collection employees )

I have put these two classes inside a context class inheriting from DbContext.

Problem is when I try to get employee data based on deptId , it throws error that department_Id column is not defined. If I remove the employees data member from Department then everything works fine. What exactly is happening here, why is it automatically adding a column, and how to tackle it?

Answer 1

Don't add deptId property to your Employee class. Just add a navigation property like this:

public virtual Department Department { get; set; }

And your Department class:

public virtual ICollection<Employee> Employees { get; set; }

Then Entity Framework will create all necessary relationships automatically for you.

For more informatin about Navigation Properties take a look at here: http://msdn.microsoft.com/en-us/data/jj713564.aspx