Entity Framework Code First create db from models - ef-code-first

Question

I am trying to use entity framework to build the database and I need some help with the models:
The models are: Company, Departments, Users, TaskType1, TaskType2, TaskType3
public class Company
{
public Company()
{
this.Departments = new HashSet<Department>();
}
public int Id { get; set;}
public string CompanyName { get; set;}
public string Address { get; set;}
public string Phone { get; set;}
public virtual ICollection<Department> Departments { get; set;}
}
public class Department
{
public Department()
{
this.Users = new HashSet<User>();
}
public int Id { get; set;}
public string Name { get; set;}
public virtual Company Company { get; set;}
public virtual ICollection<User> Users { get; set;}
}
public class User
{
public Company()
{
}
public int Id { get; set;}
public string UserName { get; set;}
public string FullName { get; set;}
public virtual Department Department { get; set;}
}
public class TaskType1
{
public TaskType1()
{
}
public int Id { get; set;}
public string Name { get; set;}
public string Description { get; set;}
public int Priority { get; set;}
}
public class TaskType2
{
public TaskType2()
{
}
public int Id { get; set;}
public string Name { get; set;}
public string Description { get; set;}
public int Priority { get; set;}
public double EstimatedCosts { get; set;}
}
public class TaskType3
{
public TaskType3()
{
}
public int Id { get; set;}
public string Name { get; set;}
public string Description { get; set;}
public int Priority { get; set;}
public bool IsDone { get; set;}
}
the reason I need to have TaskType1, TaskType2, TaskType3 as tables is because there are different types of tasks (different data/fields is needed).
How can I connect my task types to the Company and to the Department and Users so I can get results like:
all tasks per company X
all tasks assigned to department z from company x
all tasks assigned to user w from department z from company x
P.S. The task types have common and different columns

Answer 1

You need to establish relationships between your models. For example, to get all tasks per company X, you would need a companyID column in each of your Tasks tables and have that be a foreign key to the Company table. Then you can set up a navigation property in the Company model:
public virtual ICollection<TaskType1> TasksType1 { get; set; }
You use an ICollection here because a company can have multiple tasks...if each company could only have one task, you could do something like:
public virtual TaskType1 TaskType1 { get; set; }
This lets you access the tasks like so:
companies = db.Companies.Include(i => i.TasksType1);
Have you checked out the Contoso University tutorial? It has a good introduction to establishing hierchical models and the associated relationships.
http://www.asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/creating-an-entity-framework-data-model-for-an-asp-net-mvc-application
(This is the MVC version, there is also a WebForms version of the tutorial if you are so inclined)