private static void TwoContextProblem()
{
HREntities ctx1 = new HREntities();
ctx1.Database.Log = Console.WriteLine;
var dept = ctx1.Departments.Find(50);
Console.WriteLine("Before change {0}", ctx1.Entry(dept).State);
dept.DepartmentName = "New Sports";
Console.WriteLine("After change {0}", ctx1.Entry(dept).State);
ctx1.Dispose();
// dept is detached
Console.WriteLine("First context is closed!");
HREntities ctx2 = new HREntities();
ctx2.Database.Log = Console.WriteLine;
ctx2.Departments.Attach(dept);
Console.WriteLine("After attached {0}", ctx2.Entry(dept).State);
ctx2.Entry(dept).State = EntityState.Modified;
Console.WriteLine("After change {0}", ctx2.Entry(dept).State);
ctx2.SaveChanges();
}
private static void FindThenUpdateDepartment()
{
HREntities ctx = new HREntities();
ctx.Database.Log = Console.WriteLine;
var dept = ctx.Departments.Find(50);
if (dept == null)
{
Console.WriteLine("Sorry! Department not found!");
}
else
{
dept.DepartmentName = "Sports";
ctx.SaveChanges();
Console.WriteLine("Updated Successfully!");
}
}
private static void LoadTwice()
{
HREntities ctx1 = new HREntities();
ctx1.Database.Log = Console.WriteLine;
var dept = ctx1.Departments.Find(50);
dept.DepartmentName = "Sportsssss";
// ctx1.Entry(dept).State = EntityState.Detached;
var dept2 = ctx1.Departments.Find(50);
Console.WriteLine(dept2.DepartmentName);
Console.WriteLine(dept == dept2);
}
static void ListDepartments()
{
HREntities ctx = new HREntities();
ctx.Database.Log = Console.WriteLine;
var depts = from dept in ctx.Departments
select dept;
foreach (Department dept in depts)
{
Console.WriteLine("{0} - {1}",
dept.DepartmentId, dept.DepartmentName);
foreach (Employee e in dept.Employees)
{
Console.WriteLine("*** {0}", e.EmployeeName);
}
}
}
private static void DeleteDepartment()
{
HREntities ctx = new HREntities();
ctx.Database.Log = Console.WriteLine;
var dept = (from d in ctx.Departments
where d.DepartmentId == 150
select d).SingleOrDefault();
if (dept == null)
{
Console.WriteLine("Sorry! Department not found!");
}
else
{
ctx.Departments.Remove(dept);
ctx.SaveChanges();
Console.WriteLine("Deleted Successfully!");
}
}
private static void AddDepartment()
{
HREntities ctx = new HREntities();
ctx.Database.Log = Console.WriteLine;
Department dept = new Department
{
DepartmentId = 150,
DepartmentName = "Customer Support"
};
// dept is detached
ctx.Departments.Add(dept);
// dept is added
Console.ReadLine();
ctx.SaveChanges(); // Insert
Console.WriteLine("Added Dept!");
}
private static void UpdateDepartment()
{
HREntities ctx = new HREntities();
ctx.Database.Log = Console.WriteLine;
var dept = ctx.Departments.Where(d => d.DepartmentId == 150).SingleOrDefault();
Console.WriteLine("Retrieved object from db");
if (dept == null)
{
Console.WriteLine("Sorry! Department not found!");
}
else
{
dept.DepartmentName = "Customer Help";
Console.WriteLine("About to save changes! Press enter to continue..");
Console.ReadLine();
ctx.SaveChanges();
Console.WriteLine("Updated Successfully!");
}
}