private static void Main(string[] args)
{
// Initialise license and stores directory location
SamplesConfiguration.Register();
//create a unique store name
var storeName = "Films_" + Guid.NewGuid().ToString();
//connection string to the BrightstarDB service
string connectionString =
string.Format(@"Type=embedded;storesDirectory={0};StoreName={1};", SamplesConfiguration.StoresDirectory,
storeName);
// if the store does not exist it will be automatically
// created when a context is created
var ctx = new MyEntityContext(connectionString);
// create some films
var bladeRunner = ctx.Films.Create();
bladeRunner.Name = "BladeRunner";
var starWars = ctx.Films.Create();
starWars.Name = "Star Wars";
// create some actors and connect them to films
var ford = ctx.Actors.Create();
ford.Name = "Harrison Ford";
ford.DateOfBirth = new DateTime(1942, 7, 13);
ford.Films.Add(starWars);
ford.Films.Add(bladeRunner);
var hamill = ctx.Actors.Create();
hamill.Name = "Mark Hamill";
hamill.DateOfBirth = new DateTime(1951, 9, 25);
hamill.Films.Add(starWars);
// save the data
ctx.SaveChanges();
// open a new context
ctx = new MyEntityContext(connectionString);
// find an actor via LINQ
ford = ctx.Actors.FirstOrDefault(a => a.Name.Equals("Harrison Ford"));
// get his films
var films = ford.Films;
// get star wars
var sw = films.FirstOrDefault(f => f.Name.Equals("Star Wars"));
// list actors in star wars
foreach (var actor in sw.Actors)
{
var actorName = actor.Name;
Console.WriteLine(actorName);
}
foreach (var actor in ctx.Actors.Where(a => a.Name.Equals("Mark Hamill")))
{
Console.WriteLine(actor.Name + " born " + actor.DateOfBirth);
}
Console.WriteLine();
Console.WriteLine("Making changes to the store with optismistic locking enabled");
ctx = new MyEntityContext(connectionString, true);
var newFilm = ctx.Films.Create();
ctx.SaveChanges();
var newFilmId = newFilm.Id;
//use optimistic locking when creating a new context
var ctx1 = new MyEntityContext(connectionString, true);
var ctx2 = new MyEntityContext(connectionString, true);
//create a film in the first context
var film1 = ctx1.Films.FirstOrDefault(f => f.Id.Equals(newFilmId));
Console.WriteLine("First context has film with ID '{0}'", film1.Id);
//create a film in the second context
var film2 = ctx2.Films.FirstOrDefault(f => f.Id.Equals(newFilmId));
Console.WriteLine("Second context has film with ID '{0}'", film2.Id);
//attempt to change the data from both contexts
film1.Name = "Raiders of the Lost Ark";
film2.Name = "American Graffiti";
//save the data to the store
try
{
Console.WriteLine("Attempting update from one context");
ctx1.SaveChanges();
Console.WriteLine("Successfully updated the film to '{0}' in the store", film1.Name);
Console.WriteLine("Attempting a conflicting update from a different context - this should fail.");
ctx2.SaveChanges();
}
catch (TransactionPreconditionsFailedException)
{
Console.WriteLine(
"Optimistic locking enabled: the conflicting update has not been processed as the underlying data has been modified.");
}
// Shutdown Brightstar processing threads.
BrightstarService.Shutdown();
Console.WriteLine();
Console.WriteLine("Finished. Press the Return key to exit.");
Console.ReadLine();
}
