public static async Task PreparationAsync()
{
using (var context = new MenusContext())
{
bool deleted = await context.Database.EnsureDeletedAsync();
string deletedText = deleted ? "deleted" : "does not exist";
WriteLine($"database {deletedText}");
bool created = await context.Database.EnsureCreatedAsync();
string createdText = created ? "created" : "already exists";
WriteLine($"database {createdText}");
var card = new MenuCard() { Title = "Meat" };
var m1 = new Menu { MenuCard = card, Text = "Wiener Schnitzel", Price = 12.90m };
var m2 = new Menu { MenuCard = card, Text = "Goulash", Price = 8.80m };
card.Menus.AddRange(new Menu[] { m1, m2 });
context.MenuCards.Add(card);
int records = await context.SaveChangesAsync();
WriteLine($"{records} records added");
}
}
static void Main(string[] args)
{
MenusContext context = new MenusContext();
bool created = context.Database.EnsureCreated();
Console.WriteLine(created);
}
private static void ObjectTracking()
{
WriteLine(nameof(ObjectTracking));
using (var context = new MenusContext())
{
context.ChangeTracker.QueryTrackingBehavior = QueryTrackingBehavior.NoTracking;
var m1 = (from m in context.Menus.AsNoTracking()
where m.Text.StartsWith("Con")
select m).FirstOrDefault();
var m2 = (from m in context.Menus
where m.Text.Contains("(")
select m).FirstOrDefault();
if (object.ReferenceEquals(m1, m2))
{
WriteLine("the same object");
}
else
{
WriteLine("not the same");
}
ShowState(context);
}
WriteLine();
}
public static void DeleteDatabase()
{
using (var context = new MenusContext())
{
bool deleted = context.Database.EnsureDeleted();
}
}
private static async Task AddTwoRecordsWithTwoTxAsync()
{
WriteLine(nameof(AddTwoRecordsWithTwoTxAsync));
try
{
using (var context = new MenusContext())
{
WriteLine("adding two records with two transactions to the database. One record should be written, the other not....");
var card = context.MenuCards.First();
var m1 = new Menu { MenuCardId = card.MenuCardId, Text = "added", Price = 99.99m };
context.Menus.Add(m1);
int records = await context.SaveChangesAsync();
WriteLine($"{records} records added");
int hightestCardId = await context.MenuCards.MaxAsync(c => c.MenuCardId);
var mInvalid = new Menu { MenuCardId = ++hightestCardId, Text = "invalid", Price = 999.99m };
context.Menus.Add(mInvalid);
records = await context.SaveChangesAsync();
WriteLine($"{records} records added");
}
}
catch (DbUpdateException ex)
{
WriteLine($"{ex.Message}");
WriteLine($"{ex?.InnerException.Message}");
}
WriteLine();
}
public static void CreateDatabase()
{
using (var context = new MenusContext())
{
bool created = context.Database.EnsureCreated();
}
}
private static void ObjectTracking()
{
WriteLine(nameof(ObjectTracking));
using (var context = new MenusContext())
{
context.ChangeTracker.QueryTrackingBehavior = QueryTrackingBehavior.NoTracking;
var m1 = (from m in context.Menus.AsNoTracking()
where m.Text.StartsWith("Con")
select m).FirstOrDefault();
var m2 = (from m in context.Menus
where m.Text.Contains("(")
select m).FirstOrDefault();
if (object.ReferenceEquals(m1, m2))
{
WriteLine("the same object");
}
else
{
WriteLine("not the same");
}
ShowState(context);
}
WriteLine();
}
private static async Task AddTwoRecordsWithOneTxAsync()
{
WriteLine(nameof(AddTwoRecordsWithOneTxAsync));
try
{
using (var context = new MenusContext())
{
var card = context.MenuCards.First();
var m1 = new Menu { MenuCardId = card.MenuCardId, Text = "added", Price = 99.99m };
int hightestCardId = await context.MenuCards.MaxAsync(c => c.MenuCardId);
var mInvalid = new Menu { MenuCardId = ++hightestCardId, Text = "invalid", Price = 999.99m };
context.Menus.AddRange(m1, mInvalid);
WriteLine("trying to add one invalid record to the database, this should fail...");
int records = await context.SaveChangesAsync();
WriteLine($"{records} records added");
}
}
catch (DbUpdateException ex)
{
WriteLine($"{ex.Message}");
WriteLine($"{ex?.InnerException.Message}");
}
WriteLine();
}
public static void ShowState(MenusContext context)
{
foreach (EntityEntry entry in context.ChangeTracker.Entries())
{
Console.WriteLine($"type: {entry.Entity.GetType().Name}, state: {entry.State}," +
$" {entry.Entity}");
}
}
private static async Task<Menu> GetMenuAsync()
{
using (var context = new MenusContext())
{
Menu menu = await context.Menus
.Skip(2)
.FirstOrDefaultAsync();
return menu;
}
}
private static async Task CreateDatabaseAsync()
{
using (var context = new MenusContext())
{
bool created = await context.Database.EnsureCreatedAsync();
string createdText = created ? "created" : "already exists";
WriteLine($"database {createdText}");
}
}
private static async Task <Menu> GetMenuAsync()
{
using (var context = new MenusContext())
{
Menu menu = await context.Menus
.Skip(2)
.FirstOrDefaultAsync();
return(menu);
}
}
private static void InitialFill()
{
MenuCard[] cards = new MenuCard[]
{
new MenuCard {
}
};
using (var context = new MenusContext())
{
}
}
private static void UpdateUntracked(Menu m)
{
using (var context = new MenusContext())
{
ShowState(context);
// EntityEntry<Menu> entry = context.Menus.Attach(m);
// entry.State = EntityState.Modified;
context.Menus.Update(m);
ShowState(context);
context.SaveChanges();
}
}
public static void DeleteDatabase()
{
Console.Write("Delete the database? ");
string input = Console.ReadLine();
if (input.ToLower() == "y")
{
using (var context = new MenusContext())
{
bool deleted = context.Database.EnsureDeleted();
}
}
}
private static async Task UpdateUntrackedAsync(Menu m)
{
using (var context = new MenusContext())
{
ShowState(context);
//EntityEntry<Menu> entry = context.Menus.Attach(m);
//entry.State = EntityState.Modified;
context.Menus.Update(m);
ShowState(context);
await context.SaveChangesAsync();
}
}
private static void AddRecords()
{
Console.WriteLine(nameof(AddRecords));
try
{
using (var context = new MenusContext())
{
var soupCard = new MenuCard();
Menu[] soups =
{
new Menu
{
Text = "Consommé Célestine (with shredded pancake)",
Price = 4.8m,
MenuCard = soupCard
},
new Menu
{
Text = "Baked Potato Soup",
Price = 4.8m,
MenuCard = soupCard
},
new Menu
{
Text = "Cheddar Broccoli Soup",
Price = 4.8m,
MenuCard = soupCard
},
};
soupCard.Title = "Soups";
soupCard.Menus.AddRange(soups);
context.MenuCards.Add(soupCard);
ShowState(context);
int records = context.SaveChanges();
Console.WriteLine($"{records} added");
Console.WriteLine();
}
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
Console.WriteLine();
}
private static async Task UpdateUntrackedAsync(Menu m)
{
using (var context = new MenusContext())
{
ShowState(context);
//EntityEntry<Menu> entry = context.Menus.Attach(m);
//entry.State = EntityState.Modified;
context.Menus.Update(m);
ShowState(context);
await context.SaveChangesAsync();
}
}
private static void UpdateRecords()
{
Console.WriteLine(nameof(UpdateRecords));
using (var context = new MenusContext())
{
Menu menu = context.Menus
.Skip(1)
.FirstOrDefault();
ShowState(context);
menu.Price += 0.2m;
ShowState(context);
int records = context.SaveChanges();
Console.WriteLine($"{records} updated");
ShowState(context);
}
Console.WriteLine();
}
private static void ChangeUntracked()
{
Menu GetMenu()
{
using (var context = new MenusContext())
{
Menu menu = context.Menus
.Skip(2)
.FirstOrDefault();
return(menu);
}
}
Menu m = GetMenu();
m.Price += 0.7m;
UpdateUntracked(m);
}
private static async Task UpdateRecordsAsync()
{
WriteLine(nameof(UpdateRecordsAsync));
using (var context = new MenusContext())
{
Menu menu = await context.Menus
.Skip(1)
.FirstOrDefaultAsync();
ShowState(context);
menu.Price += 0.2m;
ShowState(context);
int records = await context.SaveChangesAsync();
WriteLine($"{records} updated");
ShowState(context);
}
WriteLine();
}
private static async Task UpdateRecordsAsync()
{
WriteLine(nameof(UpdateRecordsAsync));
using (var context = new MenusContext())
{
Menu menu = await context.Menus
.Skip(1)
.FirstOrDefaultAsync();
ShowState(context);
menu.Price += 0.2m;
ShowState(context);
int records = await context.SaveChangesAsync();
WriteLine($"{records} updated");
ShowState(context);
}
WriteLine();
}
private static void AddHundredRecords()
{
Console.WriteLine(nameof(AddHundredRecords));
using (var context = new MenusContext())
{
var card = context.MenuCards.FirstOrDefault();
if (card != null)
{
var menus = Enumerable.Range(1, 100).Select(x => new Menu
{
MenuCard = card,
Text = $"menu {x}",
Price = 9.9m
});
context.Menus.AddRange(menus);
int records = context.SaveChanges();
Console.WriteLine($"{records} added");
}
}
Console.WriteLine();
}
private static void ObjectTracking()
{
Console.WriteLine(nameof(ObjectTracking));
using (var context = new MenusContext())
{
var m1 = (from m in context.Menus
where m.Text.StartsWith("Con")
select m).FirstOrDefault();
var m2 = (from m in context.Menus
where m.Text.Contains("(")
select m).FirstOrDefault();
if (object.ReferenceEquals(m1, m2))
{
Console.WriteLine("the same object");
}
else
{
Console.WriteLine("not the same");
}
ShowState(context);
}
Console.WriteLine();
}
private static void AddHundredRecords()
{
Console.WriteLine(nameof(AddHundredRecords));
using (var context = new MenusContext())
{
var card = context.MenuCards.FirstOrDefault();
if (card != null)
{
var menus = Enumerable.Range(1, 100).Select(x => new Menu
{
MenuCard = card,
Text = $"menu {x}",
Price = 9.9m
});
context.Menus.AddRange(menus);
Stopwatch stopwatch = Stopwatch.StartNew();
int records = context.SaveChanges();
stopwatch.Stop();
Console.WriteLine($"{records} records added after {stopwatch.ElapsedMilliseconds} milliseconds");
}
}
Console.WriteLine();
}
private static async Task TwoSaveChangesWithOneTxAsync()
{
WriteLine(nameof(TwoSaveChangesWithOneTxAsync));
IDbContextTransaction tx = null;
try
{
using (var context = new MenusContext())
using (tx = await context.Database.BeginTransactionAsync())
{
WriteLine("using one explicit transaction, writing should roll back...");
var card = context.MenuCards.First();
var m1 = new Menu { MenuCardId = card.MenuCardId, Text = "added with explicit tx", Price = 99.99m };
context.Menus.Add(m1);
int records = await context.SaveChangesAsync();
WriteLine($"{records} records added");
int hightestCardId = await context.MenuCards.MaxAsync(c => c.MenuCardId);
var mInvalid = new Menu { MenuCardId = ++hightestCardId, Text = "invalid", Price = 999.99m };
context.Menus.Add(mInvalid);
records = await context.SaveChangesAsync();
WriteLine($"{records} records added");
tx.Commit();
}
}
catch (DbUpdateException ex)
{
WriteLine($"{ex.Message}");
WriteLine($"{ex?.InnerException.Message}");
WriteLine("rolling back...");
tx.Rollback();
}
WriteLine();
}
public static void ShowState(MenusContext context)
{
foreach (EntityEntry entry in context.ChangeTracker.Entries())
{
WriteLine($"type: {entry.Entity.GetType().Name}, state: {entry.State}, {entry.Entity}");
}
WriteLine();
}
private static async Task AddRecordsAsync()
{
WriteLine(nameof(AddRecordsAsync));
try
{
using (var context = new MenusContext())
{
var soupCard = new MenuCard();
Menu[] soups =
{
new Menu { Text = "Consommé Célestine (with shredded pancake)", Price = 4.8m, MenuCard =soupCard},
new Menu { Text = "Baked Potato Soup", Price = 4.8m, MenuCard = soupCard },
new Menu { Text = "Cheddar Broccoli Soup", Price = 4.8m, MenuCard = soupCard },
};
soupCard.Title = "Soups";
soupCard.Menus.AddRange(soups);
context.MenuCards.Add(soupCard);
ShowState(context);
int records = await context.SaveChangesAsync();
WriteLine($"{records} added");
WriteLine();
}
}
catch (Exception ex)
{
WriteLine(ex.Message);
}
WriteLine();
}