EF 自测例子
public ActionResult Test()
{
using (MvcShoppingContext db = new MvcShoppingContext())
{
var objectContext = ((IObjectContextAdapter)db).ObjectContext; //用来解决 未启用MSDTC错误
try
{
objectContext.Connection.Open();
//设置事务超时时间
//TransactionOptions transactionOption = new TransactionOptions();
//transactionOption.Timeout = new TimeSpan(0, 1, 0); //设置为1分钟
//事务处理,默认：隔离级别为可序列化 (Serializable)，事务的超时时间为 1 分钟
using (var scope = new TransactionScope())
{
//一、 单表增删改查
//1，增,--------------------------------------------------------
//Person p = new Person() { Name = "qjn", Age = 23, Gender = "female" };
//方法一
//db.Persons.Add(p);
//db.SaveChanges();
//方法二
//db.Persons.Attach(p);
//db.Entry<Person>(p).State = System.Data.EntityState.Added;
//db.SaveChanges();
//2,改,只要实体的ID就可以了 -------------------------------------------
//方法一、修改所有字段,不设置的字段将会变为类型的默认字段，如string 将为null
//Person p = new Person() { Id = 1, Name = "QinHua", Age = 30 };
//db.Persons.Attach(p);
//db.Entry<Person>(p).State = System.Data.EntityState.Modified;
//db.SaveChanges();
//方法二、先查寻出来，再修改。注意：会发生未启用MSDTC错误，请注意觖决办法
//Person p = db.Persons.SingleOrDefault(m => m.Id == 1);
//p.Name = "Qin Hua";
//p.Gender = "Male";
//db.SaveChanges();
//方法三、修改部份字段，
//Person p = new Person() { Id = 1, Name = "Hua", Age = 25 };
//db.Persons.Attach(p);
//var setEntry = ((IObjectContextAdapter)db).ObjectContext.ObjectStateManager.GetObjectStateEntry(p);
//setEntry.SetModifiedProperty("Name");
//setEntry.SetModifiedProperty("Age");
//db.SaveChanges();
//3， 删--------------------------------------------------
//Person p = new Person() { Id = 2 };
//db.Persons.Attach(p);
//db.Persons.Remove(p);
//db.SaveChanges();
//4，并发处理，如果两IE同时执行此方法，将只有一个成功，另一个出错--------------
//Person p = db.Persons.Where(m => m.Id == 3).SingleOrDefault();
//p.Name = "N-" + DateTime.Now.ToString("mm:ss");
//System.Threading.Thread.Sleep(3000);
//db.SaveChanges();
//并发冲突时的解决办法(fail)：当发生冲突时，循环执行此过程。(当然还有其它方法),这个方法有问题，会引起事务中止
//int i = 0;
//int maxTimes = 3;
//bool isHaveError = false;
//do
//{
// isHaveError = false;
// try
// {
// Person p = db.Persons.Where(m => m.Id == 3).SingleOrDefault();
// p.Name = p.Name+" N-" + DateTime.Now.ToString("mm:ss");
// System.Threading.Thread.Sleep(3000);
// db.SaveChanges();
// }
// //catch (DbUpdateConcurrencyException ex)
// //catch (System.Data.OptimisticConcurrencyException ex)
// catch(DbUpdateException ex)
// {
// //当发生冲突时
// foreach (DbEntityEntry item in ex.Entries)
// {
// objectContext.Refresh(
// System.Data.Objects.RefreshMode.StoreWins, item.Entity);
// }
// //db.SaveChanges();
// isHaveError = true;
// i++;
// }
//} while (i < maxTimes && isHaveError);
//if (i >= maxTimes)
//{
// throw new Exception("并发测试，抛出异常，数据更新过程中发生了并发错误");
//}
//并发冲突解决2(right)，由于是网站，所以用lock方式，（客户端软件可以考虑用数据库锁的方式)----------------------
//lock (lockObj)
//{
// Person p = db.Persons.Where(m => m.Id == 3).SingleOrDefault();
// p.Name = p.Name + " N-" + DateTime.Now.ToString("mm:ss");
// System.Threading.Thread.Sleep(3000);
// db.SaveChanges();
//}
//二、一对多、多对一关系处理
// 级联增 1,正向 [如果级联对象不存在，则会新增级联对象，否则不新增(如例2)]
//OrderH oh = new OrderH() { Name = "AA", OrderDs = new List<OrderD>() };
//OrderD od1 = new OrderD() { Price = 10 };
//OrderD od2 = new OrderD() { Price = 12 };
//oh.OrderDs.Add(od1);
//oh.OrderDs.Add(od2);
//db.OrderHs.Add(oh);
//db.SaveChanges();
// 级联增 2 ，加入到一个
//OrderH oh = db.OrderHs.Where(m => m.Id == 1).SingleOrDefault();
//OrderD od1 = new OrderD() { Price = 13, OrderH=oh };
//OrderD od2 = new OrderD() { Price = 14, OrderH = oh };
//db.OrderDs.Add(od1);
//db.OrderDs.Add(od2);
//db.SaveChanges();
// 级联增 2.2 ，加入到一个,[这样子会出错]
//OrderH oh = db.OrderHs.Where(m => m.Id == 5).SingleOrDefault();
//OrderD od1 = new OrderD() { Price = 13 };
//OrderD od2 = new OrderD() { Price = 14 };
//oh.OrderDs.Add(od1);
//oh.OrderDs.Add(od2);
//db.OrderHs.Add(oh);
//db.SaveChanges();
// 级联增 3，反向
//OrderH oh = new OrderH() { Name = "BB", OrderDs = new List<OrderD>() };
//OrderD od1 = new OrderD() { Price = 13, OrderH = oh };
//OrderD od2 = new OrderD() { Price = 14, OrderH = oh };
//db.OrderDs.Add(od1);
//db.OrderDs.Add(od2);
//db.SaveChanges();
// 级联增 4，各自保存各自的
//OrderH oh = new OrderH() { Name = "CC", OrderDs = new List<OrderD>() };
//OrderD od1 = new OrderD() { Price = 15, OrderH = oh };
//OrderD od2 = new OrderD() { Price = 16, OrderH = oh };
//db.OrderDs.Add(od1);
//db.OrderDs.Add(od2);
//db.OrderHs.Add(oh);
//db.SaveChanges();
// 级联增 5，各自保存各自的
//OrderH oh = new OrderH() { Name = "DD", OrderDs = new List<OrderD>() };
//OrderD od1 = new OrderD() { Price = 15, OrderH = oh };
//OrderD od2 = new OrderD() { Price = 16, OrderH = oh };
//oh.OrderDs.Add(od1);
//oh.OrderDs.Add(od2);
//db.OrderDs.Add(od1);
//db.OrderDs.Add(od2);
//db.OrderHs.Add(oh);
//db.SaveChanges();
//2,级联修改
//OrderH oh = db.OrderHs.Where(m => m.Id == 5).SingleOrDefault();
//OrderD od = null;
//foreach (var item in oh.OrderDs)
//{
// od = item;
// break;
//}
//oh.Name = "Modify";
//od.Price = 11;
//db.SaveChanges();
//3,级联删除
//只删除主键表是会出错的
//OrderH oh = db.OrderHs.Where(m => m.Id == 5).SingleOrDefault();
//db.OrderHs.Remove(oh);
//db.SaveChanges();
//只删除主键表是会出错的
//OrderH oh = new OrderH() { Id = 5 };
//db.OrderHs.Attach(oh);
//db.OrderHs.Remove(oh);
//db.SaveChanges();
//删除主表，并将子表的外键清空
//OrderH oh = db.OrderHs.Where(m => m.Id == 5).SingleOrDefault();
//OrderD od = null;
//foreach (var item in oh.OrderDs)
//{
// od = item;
// od.OrderH = null;
//}
//db.OrderHs.Remove(oh);
//db.SaveChanges();
//删除主表，并将子表的外键清空 2
//OrderH oh = db.OrderHs.Where(m => m.Id == 2).SingleOrDefault();
//oh.OrderDs.Clear();
//db.OrderHs.Remove(oh);
//db.SaveChanges();
//删除主表，并将子表删除,数据库里设置级联删除
OrderH oh = db.OrderHs.Where(m => m.Id == 1).SingleOrDefault();
db.OrderHs.Remove(oh);
db.SaveChanges();
//只将子表的外键清空 2
//OrderH oh = db.OrderHs.Where(m => m.Id == 1).SingleOrDefault();
//oh.OrderDs.Clear();
//db.SaveChanges();
//只将子表的外键清空
//OrderH oh = db.OrderHs.Where(m => m.Id == 7).SingleOrDefault();
//OrderD od = null;
//foreach (var item in oh.OrderDs)
//{
// od = item;
// od.OrderH = null;
//}
//db.SaveChanges();
//三、多对多的处理
//1,新增
//User u = new User() { Name = "qqh", NewRoles = new List<NewRole>() };
//NewRole nr = new NewRole() { Name = "r1" };
//u.NewRoles.Add(nr);
//db.Users.Add(u);
//db.SaveChanges();
//2，加入一笔新数据
//User u = new User() { Name = "hhyy", NewRoles = new List<NewRole>() };
//NewRole nr = db.NewRoles.Where(m => m.Id == 1).SingleOrDefault();
//u.NewRoles.Add(nr);
//db.Users.Add(u);
//db.SaveChanges();
//3,修改,将一个用户的角色删除
//User u = db.Users.Where(m => m.Id == 1).SingleOrDefault();
//u.Name = "tre";
//u.NewRoles.Clear(); //移除它的所有角色,中间表会清掉相关数据
//db.SaveChanges();
//4,
//throw new Exception("事务测试，抛出异常，事务将回滚");
scope.Complete();
}
}
catch (Exception ex)
{
throw ex;
}
finally
{
objectContext.Connection.Close();
}
}
return View();
}
