EntityFramework用法探索（八）事务处理

使用 前文中描述的Retail示例 ，在Customer对象的Mapping中设置Name属性：
我们构造一个有效的Customer对象，再构造一个无效的Name属性为空的对象。

   DomainModels.Customer customer1 = new DomainModels.Customer()
 2       {
 3         Name = "Dennis Gao",
 4         Address = "Beijing",
 5         Phone = "18888888888",
 6       };
 7       DomainModels.Customer customer2 = new DomainModels.Customer()
 8       {
 9         //Name = "Degang Guo", // 创造一个无效的对象，此处客户名称不能为空
10         Address = "Beijing",
11         Phone = "16666666666",
12       };

我们使用如下代码添加Customer对象数据到数据库中，

   Customer entity1 = Mapper.Map<DomainModels.Customer, Customer>(customer1);
 2       Customer entity2 = Mapper.Map<DomainModels.Customer, Customer>(customer2);
 3 
 4       using (RetailEntities context = new RetailEntities())
 5       {
 6         context.Customers.Add(entity1);
 7         context.Customers.Add(entity2);
 8         context.SaveChanges(); // 提交时将抛出异常
 9 
10         customer1.Id = entity1.Id;
11         customer2.Id = entity2.Id;
12       }
13 
14       Console.WriteLine(customer1);
15       Console.WriteLine(customer2);

EntityFramework已经明确的告诉我们某Entity验证失败。此时查询数据库，两条记录均不存在。EntityFramework自带的事务已经帮助回滚了操作。

现在我们修改下程序，改为提交两次：

  try
 2       {
 3         using (RetailEntities context = new RetailEntities())
 4         {
 5           context.Customers.Add(entity1);
 6           context.SaveChanges(); // 顺利执行
 7           context.Customers.Add(entity2);
 8           context.SaveChanges(); // 提交时将抛出异常
 9 
10           customer1.Id = entity1.Id;
11           customer2.Id = entity2.Id;
12         }
13       }
14       catch (Exception ex)
15       {
16         Console.WriteLine(FlattenException(ex));
17       }

然后我们修改代码，增加TransactionScope，

实例1

  using (var transactionScope = new TransactionScope(
 2           TransactionScopeOption.RequiresNew))
 3         {
 4           Customer entity1 = Mapper.Map<DomainModels.Customer, Customer>(customer1);
 5           Customer entity2 = Mapper.Map<DomainModels.Customer, Customer>(customer2);
 6 
 7           using (RetailEntities context = new RetailEntities())
 8           {
 9             context.Customers.Add(entity1);
10             context.SaveChanges(); // 顺利提交
11             context.Customers.Add(entity2);
12             context.SaveChanges(); // 提交时将抛出异常
13 
14             customer1.Id = entity1.Id;
15             customer2.Id = entity2.Id;
16           }
17 
18           transactionScope.Complete();
19         }
20       }
21       catch (Exception ex)
22       {
23         Console.WriteLine(FlattenException(ex));
24       }

 实例2

   using (var transactionScope = new TransactionScope(TransactionScopeOption.RequiresNew))
                {

                    //收藏
                    string collSql = @"delete from CollectDiscoverInfo where DiscoverID='{0}'";

                    collSql = string.Format(collSql, id);
                    db.Database.ExecuteSqlCommand(collSql);

                    //评论
                    string commentSql = "delete from CommentDiscoverInfo where DiscoverID='{0}'";
                    commentSql = string.Format(commentSql, id);
                    db.Database.ExecuteSqlCommand(commentSql);

                    //赞
                    string praiseSql = "delete from PraiseDiscover where DiscoverID='{0}'";
                    praiseSql = string.Format(praiseSql, id);
                    db.Database.ExecuteSqlCommand(praiseSql);

                    //图片
                    string photoSql = "delete from DiscoverPhotoInfo where DiscoverID='{0}'";

                    photoSql = string.Format(photoSql, id);
                    db.Database.ExecuteSqlCommand(photoSql);

                    //话题
                    db.DiscoverInfo.Remove(entity);
                    db.SaveChanges();

                    //提交事务
                    transactionScope.Complete();
                }