private static void Cleanup()
{
using (var context = new Recipe8Context())
{
context.Database.ExecuteSqlCommand("delete from chapter5.employee");
context.Database.ExecuteSqlCommand("delete from chapter5.department");
context.Database.ExecuteSqlCommand("delete from chapter5.company");
}
}
private static void RunExample()
{
using (var context = new Recipe8Context())
{
var company = new Company {
Name = "Acme Products"
};
var acc = new Department {
Name = "Accounting", Company = company
};
var ship = new Department {
Name = "Shipping", Company = company
};
var emp1 = new Employee {
Name = "Jill Carpenter", Department = acc
};
var emp2 = new Employee {
Name = "Steven Hill", Department = ship
};
context.Employees.Add(emp1);
context.Employees.Add(emp2);
context.SaveChanges();
}
// First approach
using (var context = new Recipe8Context())
{
// Assume we already have an employee
var jill = context.Employees.First(o => o.Name == "Jill Carpenter");
// Get Jill's Department and Company, but we also reload Employees
var results = context.Employees.Include("Department.Company")
.First(o => o.EmployeeId == jill.EmployeeId);
Console.WriteLine("{0} works in {1} for {2}", jill.Name, jill.Department.Name,
jill.Department.Company.Name);
}
// More efficient approach, does not retrieve Employee again
using (var context = new Recipe8Context())
{
// Assume we already have an employee
var jill = context.Employees.Where(o => o.Name == "Jill Carpenter").First();
// Leverage the Entry, Query and Include methods to retrieve Department and Company data
// without requerying the Employee table
context.Entry(jill).Reference(x => x.Department).Query().Include(y => y.Company).Load();
Console.WriteLine("{0} works in {1} for {2}", jill.Name, jill.Department.Name,
jill.Department.Company.Name);
}
Console.WriteLine("Press <enter> to continue...");
Console.ReadLine();
}
