EF 自带事务

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通过反编译可以看到单实例DbContext的SaveChanges方式默认开启了事务，当同时更新多条记录时，有一条失败就会RollBack。模拟测试代码

using System;using System.Collections.Generic;using System.Linq;using System.Text;using EF.Model;using EF.DAL;using System.Data.Entity;using System.Collections;using System.Transactions;namespace EF.Demo{    class Program    {        static void Main(string[] args)        {            BlogCategory cate = null;            DemoDBEntities context = new DemoDBEntities();            //DemoDBEntities context2 = new DemoDBEntities();            try            {                //using (TransactionScope scope = new TransactionScope())                //{                    //context.Configuration.LazyLoadingEnabled = false;                    DbSet<BlogCategory> set = context.Set<BlogCategory>();                    cate = new BlogCategory();                    cate.CateName = "2010-7";                    cate.CreateTime = DateTime.Now;                    cate.BlogArticle.Add(new BlogArticle() { Title = "2011-7-15" });                    set.Add(cate);                    //由于没设置Title字段,并且CreateTime字段不能为空，故会引发异常                    context.Set<BlogArticle>().Add(new BlogArticle { BlogCategory_CateID = 2 });                    int a = context.SaveChanges();                //    context2.Set<BlogArticle>().Add(new BlogArticle { BlogCategory_CateID = 2 });                //    int b = context2.SaveChanges();                //    scope.Complete();                //}            }            catch(Exception ex)            {                Console.WriteLine(ex.Message);            }                        Console.ReadLine();                   }    }    }

通过SQL SERVER Profile 监视到没有一句SQL语句被执行，SaveChanges事务是预执新所有操作成功后才会更新到数据库中。

我们再来测试一下分布式事务，创建的Context2用于模拟代表其它数据库

using System;using System.Collections.Generic;using System.Linq;using System.Text;using EF.Model;using EF.DAL;using System.Data.Entity;using System.Collections;using System.Transactions;namespace EF.Demo{    class Program    {        static void Main(string[] args)        {            BlogCategory cate = null;            DemoDBEntities context = new DemoDBEntities();            DemoDBEntities context2 = new DemoDBEntities();            try            {                using (TransactionScope scope = new TransactionScope())                {                    //context.Configuration.LazyLoadingEnabled = false;                    DbSet<BlogCategory> set = context.Set<BlogCategory>();                    cate = new BlogCategory();                    cate.CateName = "2010-7";                    cate.CreateTime = DateTime.Now;                    cate.BlogArticle.Add(new BlogArticle() { Title = "2011-7-15" });                    set.Add(cate);                    //实例1 对数据库执行提交                    int a = context.SaveChanges();                    //实例2 模拟其它数据库提交 时间字段为空，无法更新成功                    context2.Set<BlogArticle>().Add(new BlogArticle { Title="2011-7-16", BlogCategory_CateID = 2 });                    int b = context2.SaveChanges();                    scope.Complete();                }            }            catch(Exception ex)            {                Console.WriteLine(ex.Message);            }                        Console.ReadLine();                   }    }    }

通过SQL SERVER Profile 监视，虽然context实际执行了两条SQL记录，但是context2的SQL没有执行成功，导致事务回滚，所有操作都被没有执行成功。

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