private static void EditTownOptimisticConcurrencyFirstWins()
{
// The first user changes some record
var contextFirst = new SoftUniEntities();
var lastTownFirstUser =
contextFirst.Towns.OrderByDescending(t => t.TownID).First();
lastTownFirstUser.Name = "Changed by the First User";
// The second user changes the same record
var contextSecondUser = new SoftUniEntities();
var lastTownSecondUser =
contextSecondUser.Towns.OrderByDescending(t => t.TownID).First();
lastTownSecondUser.Name = "Changed by the Second User";
// Conflicting changes: first wins; second gets an exception
contextFirst.SaveChanges();
try
{
contextSecondUser.SaveChanges();
}
catch (DbUpdateConcurrencyException ex)
{
Console.WriteLine("Error: concurrent change occurred.");
Console.WriteLine(ex.Message);
}
}
private static void CreateNewTown()
{
var context = new SoftUniEntities();
var town = new Town { Name = "New Town" };
context.Towns.Add(town);
context.SaveChanges();
}
private static void CreateNewProject()
{
var context = new SoftUniEntities();
var project = new Project { Name = "New Project", StartDate = DateTime.Now };
context.Projects.Add(project);
context.SaveChanges();
}
private static void EditProjectOptimisticConcurrencyLastWins()
{
// The first user changes some record
var contextFirst = new SoftUniEntities();
var lastProjectFirstUser =
contextFirst.Projects.OrderByDescending(p => p.ProjectID).First();
lastProjectFirstUser.Name = "Changed by the First User";
// The second user changes the same record
var contextSecondUser = new SoftUniEntities();
var lastProjectSecond =
contextSecondUser.Projects.OrderByDescending(p => p.ProjectID).First();
lastProjectSecond.Name = "Changed by the Second User";
// Conflicting changes: last wins
contextFirst.SaveChanges();
contextSecondUser.SaveChanges();
}
