public static void PlayWithDetatch()
{
SoftUniEntities softUniEntities = new SoftUniEntities();
Employee newEmployee = new Employee
{
FirstName = "Vladimir",
LastName = "Georgiev",
JobTitle = "Technical Trainer",
DepartmentID = 1,
HireDate = new DateTime(2013, 12, 16),
Salary = 10000
};
softUniEntities.Employees.Add(newEmployee);
softUniEntities.SaveChanges();
// Now the employee is stored in the database. Let's print its department
Console.WriteLine(newEmployee.Department); // prints "null"
// Find the employee by primary key --> returns the same object (unmodified)
// Still prints "null" (due to caching and identity resolution)
var employeeById = softUniEntities.Employees.Find(newEmployee.EmployeeID);
Console.WriteLine(employeeById.Department); // null (due to caching)
// Find the product by query still uses "identity resolution" (caching)
var employeeFromDb =
(from emp in softUniEntities.Employees
where emp.EmployeeID == newEmployee.EmployeeID
select emp).FirstOrDefault();
Console.WriteLine(employeeFromDb.Department); // null (due to caching)
// Detach the object from the context --> remove it from the cache
((IObjectContextAdapter)softUniEntities).ObjectContext.Detach(newEmployee);
// This change will not be tracked by the context
newEmployee.FirstName = "Vlado";
// This will make no changes in the DB (detatched objects are not tracked)
softUniEntities.SaveChanges();
// Now find the product by primary key (detached entities are not cached)
var detachedEmployee = softUniEntities.Employees.Find(newEmployee.EmployeeID);
Console.WriteLine(detachedEmployee.Department); // works (no caching)
}
/// <summary>
/// Create a new Employee object.
/// </summary>
/// <param name="employeeID">Initial value of the EmployeeID property.</param>
/// <param name="lastName">Initial value of the LastName property.</param>
/// <param name="firstName">Initial value of the FirstName property.</param>
public static Employee CreateEmployee(global::System.Int32 employeeID, global::System.String lastName, global::System.String firstName)
{
Employee employee = new Employee();
employee.EmployeeID = employeeID;
employee.LastName = lastName;
employee.FirstName = firstName;
return employee;
}
/// <summary>
/// Deprecated Method for adding a new object to the Employees EntitySet. Consider using the .Add method of the associated ObjectSet<T> property instead.
/// </summary>
public void AddToEmployees(Employee employee)
{
base.AddObject("Employees", employee);
}
