Entity Framework: Get Subclass objects in Repository

Question

I have following model corresponding to the database tables listed below.

A manager is an employee. An accountant also is an employee.

What is the best method to get all managers in the repository? How to implement GetAllManagers() method?
Is it proper TPT?

enter image description here

CODE

MyRepository.MyEmployeeRepository rep = new MyEmployeeRepository();
List<Employee> e = rep.GetAllEmployees();



public class MyEmployeeRepository
{
    private string connectionStringVal;
    public MyEmployeeRepository()
    {
        SqlConnectionStringBuilder sqlBuilder = new SqlConnectionStringBuilder();
        sqlBuilder.DataSource = ".";
        sqlBuilder.InitialCatalog = "LibraryReservationSystem";
        sqlBuilder.IntegratedSecurity = true;

        // Initialize the EntityConnectionStringBuilder.
        EntityConnectionStringBuilder entityBuilder = new EntityConnectionStringBuilder();
        entityBuilder.Provider = "System.Data.SqlClient";
        entityBuilder.ProviderConnectionString = sqlBuilder.ToString();
        entityBuilder.Metadata = @"res://*/Test.csdl|res://*/Test.ssdl|res://*/Test.msl";

        connectionStringVal = entityBuilder.ToString();


    }


    public List<Employee> GetAllEmployees()
    {

        List<Employee> employees = new List<Employee>();
        using (var context = new MyEntityDataModelEDM.LibraryReservationSystemEntities1(connectionStringVal))
        {
            foreach (MyEntityDataModelEDM.Employee p in context.Employees)
            {
                employees.Add(p);
            }
        }

        return employees;
    }

    public List<Manager> GetAllManagers()
    {

        List<Manager> managers = new List<Manager>();
        using (var context = new MyEntityDataModelEDM.LibraryReservationSystemEntities1(connectionStringVal))
        {


        }

        return managers;
    }



}

EDIT

This model has drawbacks. It should consider following:

Employee can be created without any role for him.
One employee can have multiple roles.

This model has drawbacks. It should consider following: Employee can be created without any role for him. One employee can have multiple roles. — LCJ, Jul 27 '12 at 14:30

score 2 · Accepted Answer · edited May 23 '17 at 12:19

2

Just do:

return context.Employees.OfType<Accountant>().ToList()

This is however a really bad way to model employees.. if an accountant changes job, you need to kill and recreate that object..

See my answer on Inheritance vs enum properties in the domain model.

edited May 23 '17 at 12:19

Community

1
1

answered Jul 27 '12 at 07:48

Roger Johansson

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I would do it using Roles, e.g. an employee or person could have a set of roles assigned to it. – Roger Johansson Jul 27 '12 at 08:52
1

And let the behavior reside in the roles instead, this way, you don't have to kill each employee every time they get a new position.. – Roger Johansson Jul 27 '12 at 08:52
1

Also, the behavior of managers and accountants probably belong to different bounded contexts. – Roger Johansson Jul 27 '12 at 08:56

Entity Framework: Get Subclass objects in Repository

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