Avevo già accennato al concetto di Object Identity in LINQ To SQl tempo fa, ultimamente, parlando di LINQ To SQL, mi diverto a mettere in crisi chi mi ascolta mostrando questo esempio:
//Read 'ALFKI' entry from Nothwind...
MyDataContext db = new MyDataContext();
Customer cust = db.Customers.Where(c => c.CustomerID == "ALFKI").Single<Customer>();
Console.WriteLine("ALFKI Customer's city is:" + cust.City);
//Updates ALFKI City to London
string query = "UPDATE Customers SET City={0} WHERE CustomerID={1}";
int ret = db.ExecuteCommand(query, "London", "ALFKI");
Console.WriteLine("{0} record updated", ret);
//Queries all customers living in London...
Console.WriteLine("Geting customers in London...");
IQueryable<Customer> custInBerlin = db.Customers.Where(c => c.City == "London");
foreach (Customer c in custInBerlin)
{
Console.WriteLine("{0} lives in {1}",c.CustomerID, c.City);
}
L'output...