//一个SaveChanges插入一次
private static void AddTwoRecordsWithTwoTx()
{
Console.WriteLine(nameof(AddTwoRecordsWithTwoTx));
try
{
using (var context = new MenusContext())
{
Console.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 = context.SaveChanges();
Console.WriteLine($"{records} records added");
int hightestCardId = context.MenuCards.Max(c => c.MenuCardId);
var mInvalid = new Menu {
MenuCardId = ++hightestCardId, Text = "invalid", Price = 999.99m
};
context.Menus.Add(mInvalid);
records = context.SaveChanges();
Console.WriteLine($"{records} records added");
}
}
catch (DbUpdateException ex)
{
Console.WriteLine($"{ex.Message}");
Console.WriteLine($"{ex?.InnerException.Message}");
}
Console.WriteLine();
}
//创建数据库及数据表
private static void CreateDatabase()
{
using (var context = new MenusContext())
{
bool created = context.Database.EnsureCreated();
}
}
//删除数据库
private static void DeleteDatabase()
{
Console.WriteLine("是否删除数据库 ？");
string input = Console.ReadLine();
if (input.ToLower() == "y")
{
using (var context = new MenusContext())
{
bool deleted = context.Database.EnsureDeleted();
}
}
}
private static void AddTwoRecordsWithOneTx()
{
Console.WriteLine(nameof(AddTwoRecordsWithOneTx));
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 = context.MenuCards.Max(c => c.MenuCardId);
Console.WriteLine($"最大的Id为：{ hightestCardId}");
var mInvalid = new Menu
{
MenuCardId = ++hightestCardId,
Text = "invalid", Price = 999.99m
};
Console.WriteLine($"m1的MenuCardId={m1.MenuCardId}");
Console.WriteLine($"mInvalid的MenuCardId={mInvalid.MenuCardId}");
context.Menus.AddRange(m1, mInvalid);
Console.WriteLine("trying to add one invalid record to the database, this should fail...");
int records = context.SaveChanges();
Console.WriteLine($"{records} 条记录被增加！");
}
}
catch (DbUpdateException ex)
{
Console.WriteLine($"{ex.Message}");
Console.WriteLine($"{ex?.InnerException.Message}");
}
Console.WriteLine();
}