diff --git a/OpenAuth.App/FlowInstanceApp.cs b/OpenAuth.App/FlowInstanceApp.cs
index 97e960de..0e18a5f4 100644
--- a/OpenAuth.App/FlowInstanceApp.cs
+++ b/OpenAuth.App/FlowInstanceApp.cs
@@ -436,7 +436,7 @@ namespace OpenAuth.App
 
         public void Update(FlowInstance flowScheme)
         {
-            Repository.Update(u => u.Id == flowScheme.Id, u => new FlowInstance());
+            Repository.Update(flowScheme);
         }
 
         public TableData Load(QueryFlowInstanceListReq request)
diff --git a/OpenAuth.Repository/BaseRepository.cs b/OpenAuth.Repository/BaseRepository.cs
index ab0e1f35..e65a493d 100644
--- a/OpenAuth.Repository/BaseRepository.cs
+++ b/OpenAuth.Repository/BaseRepository.cs
@@ -30,7 +30,7 @@ namespace OpenAuth.Repository
         }
 
         /// <summary>
-        /// 查找单个
+        /// 查找单个，且不被上下文所跟踪
         /// </summary>
         public T FindSingle(Expression<Func<T, bool>> exp)
         {
@@ -87,9 +87,14 @@ namespace OpenAuth.Repository
         public void Update(T entity)
         {
             var entry = this.Context.Entry(entity);
-            //todo:如果状态没有任何更改，会报错
             entry.State = EntityState.Modified;
 
+            //如果数据没有发生变化
+            if (!this.Context.ChangeTracker.HasChanges())
+            {
+                return;
+            }
+
             Save();
         }
 
diff --git a/OpenAuth.Repository/OpenAuthDBContext.cs b/OpenAuth.Repository/OpenAuthDBContext.cs
index b1e0dad7..ea89daca 100644
--- a/OpenAuth.Repository/OpenAuthDBContext.cs
+++ b/OpenAuth.Repository/OpenAuthDBContext.cs
@@ -19,9 +19,13 @@ namespace OpenAuth.Repository
         {
             Database.SetInitializer< OpenAuthDBContext>(null);
         }
+
         public OpenAuthDBContext()
-            :base("Name=OpenAuthDBContext")
-        { }
+            : base("Name=OpenAuthDBContext")
+        {
+            // 关闭语义可空判断
+            Configuration.UseDatabaseNullSemantics = true;
+        }
 
         public OpenAuthDBContext(string nameOrConnectionString)
             : base(nameOrConnectionString)
diff --git a/OpenAuth.Repository/UnitWork.cs b/OpenAuth.Repository/UnitWork.cs
index 91a7e88b..1c48bef6 100644
--- a/OpenAuth.Repository/UnitWork.cs
+++ b/OpenAuth.Repository/UnitWork.cs
@@ -1,151 +1,151 @@
-using System;
-using System.Data.Entity;
-using System.Data.Entity.Migrations;
-using System.Data.Entity.Validation;
-using System.Linq;
-using System.Linq.Expressions;
-using EntityFramework.Extensions;
-using Infrastructure;
-using OpenAuth.Repository.Interface;
-
-namespace OpenAuth.Repository
-{
-   public  class UnitWork: IUnitWork
-   {
-       protected OpenAuthDBContext Context = new OpenAuthDBContext();
-
-
-       /// <summary>
-        /// 根据过滤条件，获取记录
-        /// </summary>
-        /// <param name="exp">The exp.</param>
-        public IQueryable<T> Find<T>(Expression<Func<T, bool>> exp = null) where T : class 
-        {
-            return Filter(exp);
-        }
-
-        public bool IsExist<T>(Expression<Func<T, bool>> exp) where T : class
-        {
-            return Context.Set<T>().Any(exp);
-        }
-
-        /// <summary>
-        /// 查找单个
-        /// </summary>
-        public T FindSingle<T>(Expression<Func<T, bool>> exp) where T:class 
-        {
-            return Context.Set<T>().AsNoTracking().FirstOrDefault(exp);
-        }
-
-        /// <summary>
-        /// 得到分页记录
-        /// </summary>
-        /// <param name="pageindex">The pageindex.</param>
-        /// <param name="pagesize">The pagesize.</param>
-        /// <param name="orderby">排序，格式如："Id"/"Id descending"</param>
-        public IQueryable<T> Find<T>(int pageindex, int pagesize, string orderby = "", Expression<Func<T, bool>> exp = null) where T : class
-        {
-            if (pageindex < 1) pageindex = 1;
-            if (string.IsNullOrEmpty(orderby))
-                orderby = "Id descending";
-
-            return Filter(exp).OrderBy(orderby).Skip(pagesize * (pageindex - 1)).Take(pagesize);
-        }
-
-        /// <summary>
-        /// 根据过滤条件获取记录数
-        /// </summary>
-        public int GetCount<T>(Expression<Func<T, bool>> exp = null) where T : class
-        {
-            return Filter(exp).Count();
-        }
-
-        public void Add<T>(T entity) where T : Domain.Entity
-        {
-            if (string.IsNullOrEmpty(entity.Id))
-            {
-                entity.Id = Guid.NewGuid().ToString();
-            }
-            Context.Set<T>().Add(entity);
-        }
-
-        /// <summary>
-        /// 批量添加
-        /// </summary>
-        /// <param name="entities">The entities.</param>
-        public void BatchAdd<T>(T[] entities) where T : Domain.Entity
-        {
-            foreach (var entity in entities)
-            {
-                entity.Id = Guid.NewGuid().ToString();
-            }
-            Context.Set<T>().AddRange(entities);
-        }
-
-        public void Update<T>(T entity) where T:class
-        {
-            var entry = this.Context.Entry(entity);
-            //todo:如果状态没有任何更改，会报错
-            entry.State = EntityState.Modified;
-
-        }
-
-        public void Delete<T>(T entity) where T:class
-        {
-            Context.Set<T>().Remove(entity);
-        }
-
-        /// <summary>
-        /// 按指定id更新实体,会更新整个实体
-        /// </summary>
-        /// <param name="identityExp">The identity exp.</param>
-        /// <param name="entity">The entity.</param>
-        public void Update<T>(Expression<Func<T, object>> identityExp, T entity) where T:class
-        {
-            Context.Set<T>().AddOrUpdate(identityExp, entity);
-        }
-
-        /// <summary>
-        /// 实现按需要只更新部分更新
-        /// <para>如：Update(u =>u.Id==1,u =>new User{Name="ok"});</para>
-        /// </summary>
-        /// <param name="where">The where.</param>
-        /// <param name="entity">The entity.</param>
-        public void Update<T>(Expression<Func<T, bool>> where, Expression<Func<T, T>> entity) where T:class
-        {
-            Context.Set<T>().Where(where).Update(entity);
-        }
-
-        public virtual void Delete<T>(Expression<Func<T, bool>> exp) where T : class
-        {
-            Context.Set<T>().Where(exp).Delete();
-        }
-
-        public void Save()
-        {
-            try
-            {
-                Context.SaveChanges();
-            }
-            catch (DbEntityValidationException e)
-            {
-                throw new Exception(e.EntityValidationErrors.First().ValidationErrors.First().ErrorMessage);
-            }
-          
-        }
-
-        private IQueryable<T> Filter<T>(Expression<Func<T, bool>> exp) where T : class
-        {
-            var dbSet = Context.Set<T>().AsQueryable();
-            if (exp != null)
-                dbSet = dbSet.Where(exp);
-            return dbSet;
-        }
-
-       public void ExecuteSql(string sql)
+using System;
+using System.Data.Entity;
+using System.Data.Entity.Migrations;
+using System.Data.Entity.Validation;
+using System.Linq;
+using System.Linq.Expressions;
+using EntityFramework.Extensions;
+using Infrastructure;
+using OpenAuth.Repository.Interface;
+
+namespace OpenAuth.Repository
+{
+   public  class UnitWork: IUnitWork
+   {
+       protected OpenAuthDBContext Context = new OpenAuthDBContext();
+
+
+       /// <summary>
+        /// 根据过滤条件，获取记录
+        /// </summary>
+        /// <param name="exp">The exp.</param>
+        public IQueryable<T> Find<T>(Expression<Func<T, bool>> exp = null) where T : class 
+        {
+            return Filter(exp);
+        }
+
+        public bool IsExist<T>(Expression<Func<T, bool>> exp) where T : class
+        {
+            return Context.Set<T>().Any(exp);
+        }
+
+        /// <summary>
+        /// 查找单个
+        /// </summary>
+        public T FindSingle<T>(Expression<Func<T, bool>> exp) where T:class 
+        {
+            return Context.Set<T>().AsNoTracking().FirstOrDefault(exp);
+        }
+
+        /// <summary>
+        /// 得到分页记录
+        /// </summary>
+        /// <param name="pageindex">The pageindex.</param>
+        /// <param name="pagesize">The pagesize.</param>
+        /// <param name="orderby">排序，格式如："Id"/"Id descending"</param>
+        public IQueryable<T> Find<T>(int pageindex, int pagesize, string orderby = "", Expression<Func<T, bool>> exp = null) where T : class
+        {
+            if (pageindex < 1) pageindex = 1;
+            if (string.IsNullOrEmpty(orderby))
+                orderby = "Id descending";
+
+            return Filter(exp).OrderBy(orderby).Skip(pagesize * (pageindex - 1)).Take(pagesize);
+        }
+
+        /// <summary>
+        /// 根据过滤条件获取记录数
+        /// </summary>
+        public int GetCount<T>(Expression<Func<T, bool>> exp = null) where T : class
+        {
+            return Filter(exp).Count();
+        }
+
+        public void Add<T>(T entity) where T : Domain.Entity
+        {
+            if (string.IsNullOrEmpty(entity.Id))
+            {
+                entity.Id = Guid.NewGuid().ToString();
+            }
+            Context.Set<T>().Add(entity);
+        }
+
+        /// <summary>
+        /// 批量添加
+        /// </summary>
+        /// <param name="entities">The entities.</param>
+        public void BatchAdd<T>(T[] entities) where T : Domain.Entity
+        {
+            foreach (var entity in entities)
+            {
+                entity.Id = Guid.NewGuid().ToString();
+            }
+            Context.Set<T>().AddRange(entities);
+        }
+
+        public void Update<T>(T entity) where T:class
+        {
+            var entry = this.Context.Entry(entity);
+            //todo:如果状态没有任何更改，会报错
+            entry.State = EntityState.Modified;
+
+        }
+
+        public void Delete<T>(T entity) where T:class
+        {
+            Context.Set<T>().Remove(entity);
+        }
+
+        /// <summary>
+        /// 按指定id更新实体,会更新整个实体
+        /// </summary>
+        /// <param name="identityExp">The identity exp.</param>
+        /// <param name="entity">The entity.</param>
+        public void Update<T>(Expression<Func<T, object>> identityExp, T entity) where T:class
+        {
+            Context.Set<T>().AddOrUpdate(identityExp, entity);
+        }
+
+        /// <summary>
+        /// 实现按需要只更新部分更新
+        /// <para>如：Update(u =>u.Id==1,u =>new User{Name="ok"});</para>
+        /// </summary>
+        /// <param name="where">The where.</param>
+        /// <param name="entity">The entity.</param>
+        public void Update<T>(Expression<Func<T, bool>> where, Expression<Func<T, T>> entity) where T:class
+        {
+            Context.Set<T>().Where(where).Update(entity);
+        }
+
+        public virtual void Delete<T>(Expression<Func<T, bool>> exp) where T : class
+        {
+            Context.Set<T>().Where(exp).Delete();
+        }
+
+        public void Save()
+        {
+            try
+            {
+                Context.SaveChanges();
+            }
+            catch (DbEntityValidationException e)
+            {
+                throw new Exception(e.EntityValidationErrors.First().ValidationErrors.First().ErrorMessage);
+            }
+          
+        }
+
+        private IQueryable<T> Filter<T>(Expression<Func<T, bool>> exp) where T : class
+        {
+            var dbSet = Context.Set<T>().AsQueryable();
+            if (exp != null)
+                dbSet = dbSet.Where(exp);
+            return dbSet;
+        }
+
+       public void ExecuteSql(string sql)
        {
             Context.Database.ExecuteSqlCommand(sql);
-        }
-
-    }
-}
+        }
+
+    }
+}
diff --git a/OpenAuth.UnitTest/TestWorkflow.cs b/OpenAuth.UnitTest/TestWorkflow.cs
index 7504efa5..e3971848 100644
--- a/OpenAuth.UnitTest/TestWorkflow.cs
+++ b/OpenAuth.UnitTest/TestWorkflow.cs
@@ -49,5 +49,12 @@ namespace OpenAuth.UnitTest
             Console.WriteLine(JsonHelper.Instance.Serialize(result.Result.FrmPreviewHtml));
         }
 
+        [TestMethod]
+        public void TestUpdate()
+        { //测试数据没有任何修改时EF报错的问题
+            var instance = _runApp.Get("d73e4412-9c49-4511-a30e-0d2f844afcee");
+            _runApp.Update(instance);
+        }
+
     }
 }