public static void ChangeTracker()
{
using (var context = new ErpContext())
{
context.Customers.Take(10).ToList();
var customer = context.Customers.First();
Console.WriteLine($"Zuvor: {customer.Name1} {customer.Name2}");
Console.WriteLine($"HasChanges? {context.ChangeTracker.HasChanges()}");
customer.Name1 = "Luis";
Console.WriteLine($"Danach: {customer.Name1} {customer.Name2}");
Console.WriteLine($"HasChanges? {context.ChangeTracker.HasChanges()}");
Console.WriteLine();
Console.WriteLine("Elemente im Changetracker:");
foreach (var entry in context.ChangeTracker.Entries <Customer>())
{
Console.WriteLine(entry.State);
}
//context.SaveChanges();
}
}
public static void IQueryableExample()
{
using (var context = new ErpContext())
{
var result = context.Orders.OrderBy(o => o.Date).Where(o => o.Price > 500);
var x = result.Where(o => o.Price < 2000).ToList();
}
}
public static void Test()
{
using (var context = new ErpContext())
{
var customer = context.Customers.Take(50);
foreach (var c in customer)
{
Console.WriteLine($"{c.Name1} {c.Name2}");
}
}
}
public static void PreLoading()
{
using (var context = new ErpContext())
{
context.Customers.First();
var orders = context.Orders.Take(20);
foreach (var o in orders)
{
Console.WriteLine($"{o.Date.ToString("dd.mm.yyy")} - {o.Customer.Name1}");
}
}
}
public static void TestChangeLoggerTest()
{
using (var context = new ErpContext())
{
var identityService = new IdentityService();
var dateTimeManager = new DateTimeManager();
var changesFinder = new ChangesFinder(identityService, dateTimeManager);
var changeLogger = new ConsoleChangeLogger(changesFinder);
var unitOfWork = new UnitOfWork(context, changeLogger);
var customer = context.Customers.First();
customer.Name1 = "Max";
customer.Name2 = "Lustig";
unitOfWork.Complete();
}
}
public static void LazyLoading() // Stand Juni 2017 - Nicht in EF Core
{
using (var context = new ErpContext())
{
// In den Entity Klassen müssen alle Navigationsproperties virtual sein
context.Configuration.LazyLoadingEnabled = true; // Standard -> true
var customers = context.Customers.Take(150).ToList();
foreach (var c in customers)
{
Console.WriteLine($"{c.Name1} {c.Name2}");
foreach (var o in c.Orders) // N + 1 Problem
{
Console.WriteLine($"\t{o.Date.ToString("dd.mm.yyyy")}");
}
}
}
}
public static void EagerLoading()
{
using (var context = new ErpContext())
{
context.Database.Log = Console.WriteLine;
var customers = context.Customers.Include(c => c.Orders)
.Where(c => c.Orders.All(o => o.Price < 500))
.Take(150).ToList();
foreach (var c in customers)
{
Console.WriteLine($"{c.Name1} {c.Name2}");
foreach (var o in c.Orders)
{
Console.WriteLine($"\t{o.Date.ToString("dd.mm.yyyy")}");
}
}
}
}
public static void AsNoTracking()
{
Customer c;
using (var context = new ErpContext())
{
var customers = context.Customers.AsNoTracking().Take(10).ToList();
foreach (var entry in context.ChangeTracker.Entries())
{
Console.WriteLine(entry.State);
}
Console.WriteLine("10 geladen");
c = customers.First();
var orders = context.Orders.Where(o => o.CustomerId == c.Id).ToList();
//c.Name1 = "";
//context.Customers.Attach(c);
//context.Entry(c).Property(cus => cus.Name1).IsModified = true;
//Console.WriteLine("Einer attached.");
//foreach (var entry in context.ChangeTracker.Entries())
// Console.WriteLine(entry.State);
}
using (var context = new ErpContext())
{
context.Customers.Attach(c);
Console.WriteLine("Am neuen Context.");
foreach (var entry in context.ChangeTracker.Entries())
{
Console.WriteLine(entry.State);
}
}
}
public static void Linq()
{
// Language integrated Query
using (var context = new ErpContext())
{
#region Restriction
// Linq
//var query = from c in context.Customers
// where c.Orders.Count > 20
// select c;
// Fluent API
//var query = context.Customers.Where(c => c.Orders.Count > 20);
//foreach (var c in query)
//{
// Console.WriteLine(c.Name1);
//}
#endregion
#region Ordering
// Linq
//var query = from o in context.Orders
// orderby o.Price ascending, o.Description descending
// select o;
//// Fluent API
//var query = context.Orders.OrderByDescending(o => o.Price).ThenBy(o => o.Description);
//foreach (var o in query)
//{
// Console.WriteLine(o.Price);
//}
#endregion
#region Projection
//var query = from o in context.Orders
// select new { Kosten = o.Price, Datum = o.Date };
//var query = context.Orders.Select(o => new { Kosten = o.Price, Datum = o.Date });
//foreach (var o in query)
//{
// Console.WriteLine(o.Kosten);
//}
#endregion
#region Grouping
//var query = from o in context.Orders
// group o by o.Date.Year into g
// select new { Year = g.Key, Orders = g };
//var query = context.Orders.GroupBy(o => o.Date.Year)
// .Select(g => new { Year = g.Key, Orders = g });
//foreach (var item in query)
//{
// Console.WriteLine(item.Year);
// foreach (var o in item.Orders)
// {
// Console.WriteLine($"\t{o.Price, 10}");
// }
//}
#endregion
#region Inner Join
//var query = from o in context.Orders
// join c in context.Customers on o.CustomerId equals c.Id
// select new { Firstname = c.Name1, o.Price };
//var query = context.Orders.Join(
// inner: context.Customers,
// outerKeySelector: o => o.CustomerId,
// innerKeySelector: c => c.Id,
// resultSelector: (o, c) => new { Firstname = c.Name1, o.Price });
//foreach (var item in query)
//{
// Console.WriteLine($"{item.Firstname} - {item.Price}");
//}
#endregion
#region Group Join
//var query = from c in context.Customers
// join o in context.Orders on c.Id equals o.CustomerId into g
// select new { Firstname = c.Name1, Orders = g.Count() };
//var query = context.Customers.GroupJoin(
// inner: context.Orders,
// outerKeySelector: c => c.Id,
// innerKeySelector: o => o.CustomerId,
// resultSelector: (c, g) => new { Firstname = c.Name1, Orders = g.Count() });
//foreach (var item in query)
//{
// Console.WriteLine($"{item.Firstname} {item.Orders}");
//}
#endregion
#region Cross Join
//var query = (from c in context.Customers
// from o in context.Orders
// select new { Firstname = c.Name1, Price = o.Price }).ToList();
//var query1 = context.Customers.SelectMany(_ => context.Orders,
// (c, o) => new { Firstname = c.Name1, Price = o.Price }).ToList();
//foreach (var item in query)
//{
// Console.WriteLine($"{item.Firstname} - {item.Price}");
//}
#endregion
#region Element Operators
//var customer = context.Customers.First();
//var customer = context.Customers.FirstOrDefault();
//var customer = context.Customers.First(c => c.Name1.StartsWith("A"));
//var customer = context.Customers.FirstOrDefault(c => c.Name1.StartsWith("A"));
//var customer = context.Customers.Single();
//var customer = context.Customers.SingleOrDefault();
//var customer = context.Customers.Single(c => c.Name1.StartsWith("A"));
//var customer = context.Customers.SingleOrDefault(c => c.Name1.StartsWith("A"));
// Wird von SQL Server nicht unterstützt!
//var customer = context.Customers.Last();
//var customer = context.Customers.LastOrDefault();
//var customer = context.Customers.Last(c => c.Name1.StartsWith("A"));
//var customer = context.Customers.LastOrDefault(c => c.Name1.StartsWith("A"));
#endregion
#region Quantifying
//var allOrdersInYear2000 = context.Orders.All(o => o.Date.Year == 2000);
//var anyOrdersInYear2000 = context.Orders.Any(o => o.Date.Year == 2000);
#endregion
#region Aggregating
//var count = context.Customers.Count();
//var count = context.Customers.Count(c => c.Name1.StartsWith("A"));
var max = context.Orders.Max(o => o.Price);
var min = context.Orders.Min(o => o.Price);
var avg = context.Orders.Average(o => o.Price);
var sum = context.Orders.Sum(o => o.Price);
#endregion
}
}
private async static void CreateSampleData()
{
var customerFiller = new Filler <Customer>();
customerFiller.Setup()
.OnProperty(c => c.Id).IgnoreIt()
.OnProperty(c => c.Orders).IgnoreIt()
.OnProperty(c => c.Name1).Use(new RealNames(NameStyle.FirstName))
.OnProperty(c => c.Name2).Use(new RealNames(NameStyle.LastName))
.OnProperty(c => c.Telephone).Use(new PatternGenerator("0049 {C:1000}-{C:100} {C:10} {C:1000}"));
var orderFiller = new Filler <Order>();
orderFiller.Setup()
.OnProperty(o => o.Id).IgnoreIt()
.OnProperty(o => o.Customer).IgnoreIt()
.OnProperty(o => o.CustomerId).IgnoreIt()
.OnProperty(o => o.Articles).IgnoreIt()
.OnProperty(o => o.Price).IgnoreIt()
.OnProperty(o => o.Description).Use(new Lipsum(LipsumFlavor.InDerFremde))
.OnProperty(o => o.Date).Use(new DateTimeRange(DateTime.Now.AddYears(-20)));
var articleFiller = new Filler <Article>();
articleFiller.Setup()
.OnProperty(a => a.Id).IgnoreIt()
.OnProperty(a => a.Orders).IgnoreIt()
.OnProperty(a => a.Description).Use(new Lipsum(LipsumFlavor.InDerFremde))
.OnProperty(a => a.Price).Use(new DoubleRange(5, 5000))
.OnProperty(a => a.Name).Use(new RandomListItem <string>(
"Apfel", "Birne", "Dampfschiff", "Akkuschrauber", "Kirschbaum", "iPhone", "Leder Geldbörse",
"Fineliner", "Notizblock", "Skateboard", "Pkw", "Besteck", "Öltanker", "LED", "Fernseher",
"Plattenspieler", "CD", "LP", "Flipchart", "Ziegelstein"));
var random = new Random();
var customers = customerFiller.Create(500);
foreach (var c in customers)
{
var actualOrders = orderFiller.Create(random.Next(1, 100));
foreach (var o in actualOrders)
{
c.Orders.Add(o);
}
}
var articles = articleFiller.Create(1000).ToList();
var orders = customers.SelectMany(c => c.Orders);
foreach (var o in orders)
{
for (int i = 0; i < random.Next(1, 50); i++)
{
o.Articles.Add(articles[random.Next(0, articles.Count - 1)]);
}
o.Price = o.Articles.Sum(a => a.Price);
}
using (var context = new ErpContext())
{
context.Customers.AddRange(customers);
await context.SaveChangesAsync();
Console.WriteLine("Fertig");
}
}