diff --git a/Bootstrap.DataAccess/DbManager.cs b/Bootstrap.DataAccess/DbManager.cs
index af473a18..1e9fb503 100644
--- a/Bootstrap.DataAccess/DbManager.cs
+++ b/Bootstrap.DataAccess/DbManager.cs
@@ -18,13 +18,7 @@ namespace Bootstrap.DataAccess
         /// <returns></returns>
         public static IDatabase Create(string connectionName = null, bool keepAlive = false)
         {
-            if (Mappers.GetMapper(typeof(Exceptions), null) == null)
-            {
-                lock (_locker)
-                {
-                    if (Mappers.GetMapper(typeof(Exceptions), null) == null) Mappers.Register(typeof(Exceptions).Assembly, new BootstrapDataAccessConventionMapper());
-                }
-            }
+            if (Mappers.GetMapper(typeof(Exceptions), null) == null) Mappers.Register(typeof(Exceptions).Assembly, new BootstrapDataAccessConventionMapper());
             var db = Longbow.Data.DbManager.Create(connectionName, keepAlive);
             db.ExceptionThrown += (sender, args) => args.Exception.Log(new NameValueCollection() { ["LastCmd"] = db.LastCommand });
             return db;
diff --git a/Bootstrap.DataAccess/Helper/DictHelper.cs b/Bootstrap.DataAccess/Helper/DictHelper.cs
index e78f48ef..30e82fc0 100644
--- a/Bootstrap.DataAccess/Helper/DictHelper.cs
+++ b/Bootstrap.DataAccess/Helper/DictHelper.cs
@@ -60,7 +60,6 @@ namespace Bootstrap.DataAccess
         {
             if (RetrieveSystemModel() && !string.IsNullOrEmpty(p.Id) && RetrieveProtectedDicts().Any(m => m.Id == p.Id)) return true;
 
-            if (p.Id == string.Empty) p.Id = null;
             var ret = DbContextManager.Create<Dict>().Save(p);
             if (ret) CacheCleanUtility.ClearCache(dictIds: new List<string>());
             return ret;
diff --git a/Bootstrap.DataAccess/Helper/GroupHelper.cs b/Bootstrap.DataAccess/Helper/GroupHelper.cs
index 1a0e88bc..807233b4 100644
--- a/Bootstrap.DataAccess/Helper/GroupHelper.cs
+++ b/Bootstrap.DataAccess/Helper/GroupHelper.cs
@@ -51,7 +51,6 @@ namespace Bootstrap.DataAccess
         /// <returns></returns>
         public static bool Save(Group p)
         {
-            if (p.Id == string.Empty) p.Id = null;
             var ret = DbContextManager.Create<Group>().Save(p);
             if (ret) CacheCleanUtility.ClearCache(groupIds: string.IsNullOrEmpty(p.Id) ? new List<string>() : new List<string>() { p.Id });
             return ret;
diff --git a/Bootstrap.DataAccess/Helper/LogHelper.cs b/Bootstrap.DataAccess/Helper/LogHelper.cs
index 394e16c7..1bef5919 100644
--- a/Bootstrap.DataAccess/Helper/LogHelper.cs
+++ b/Bootstrap.DataAccess/Helper/LogHelper.cs
@@ -34,7 +34,6 @@ namespace Bootstrap.DataAccess
         /// <returns></returns>
         public static bool Save(Log log)
         {
-            if (log.Id == string.Empty) log.Id = null;
             log.LogTime = DateTime.Now;
             return DbContextManager.Create<Log>().Save(log);
         }
diff --git a/Bootstrap.DataAccess/Helper/LoginHelper.cs b/Bootstrap.DataAccess/Helper/LoginHelper.cs
index 430eafbb..bbd19c9d 100644
--- a/Bootstrap.DataAccess/Helper/LoginHelper.cs
+++ b/Bootstrap.DataAccess/Helper/LoginHelper.cs
@@ -18,7 +18,6 @@ namespace Bootstrap.DataAccess
         /// <returns></returns>
         public static bool Log(LoginUser user)
         {
-            if (user.Id == string.Empty) user.Id = null;
             if (string.IsNullOrEmpty(user.UserName)) user.UserName = user.Ip;
             return DbContextManager.Create<LoginUser>().Log(user);
         }
diff --git a/Bootstrap.DataAccess/Helper/MenuHelper.cs b/Bootstrap.DataAccess/Helper/MenuHelper.cs
index 22ceba03..aca1d932 100644
--- a/Bootstrap.DataAccess/Helper/MenuHelper.cs
+++ b/Bootstrap.DataAccess/Helper/MenuHelper.cs
@@ -32,7 +32,6 @@ namespace Bootstrap.DataAccess
             // 不允许保存系统菜单与前台演示系统的默认菜单
             if (DictHelper.RetrieveSystemModel() && (p.Category == "0" || p.Application == "2")) return true;
 
-            if (p.Id == string.Empty) p.Id = null;
             var ret = DbContextManager.Create<Menu>().Save(p);
             if (ret) CacheCleanUtility.ClearCache(menuIds: string.IsNullOrEmpty(p.Id) ? new List<string>() : new List<string>() { p.Id });
             return ret;
diff --git a/Bootstrap.DataAccess/Helper/MessageHelper.cs b/Bootstrap.DataAccess/Helper/MessageHelper.cs
index 2e1a8a6e..12150daf 100644
--- a/Bootstrap.DataAccess/Helper/MessageHelper.cs
+++ b/Bootstrap.DataAccess/Helper/MessageHelper.cs
@@ -54,10 +54,6 @@ namespace Bootstrap.DataAccess
         /// </summary>
         /// <param name="msg"></param>
         /// <returns></returns>
-        public static bool Save(Message msg)
-        {
-            if (string.IsNullOrEmpty(msg.Id)) msg.Id = null;
-            return DbContextManager.Create<Message>().Save(msg);
-        }
+        public static bool Save(Message msg) => DbContextManager.Create<Message>().Save(msg);
     }
 }
diff --git a/Bootstrap.DataAccess/Helper/ResetUserHelper.cs b/Bootstrap.DataAccess/Helper/ResetUserHelper.cs
index ca61c295..6b1e7d5a 100644
--- a/Bootstrap.DataAccess/Helper/ResetUserHelper.cs
+++ b/Bootstrap.DataAccess/Helper/ResetUserHelper.cs
@@ -14,7 +14,6 @@ namespace Bootstrap.DataAccess
         /// <returns></returns>
         public static bool Save(ResetUser user)
         {
-            if (user.Id == string.Empty) user.Id = null;
             user.ResetTime = DateTime.Now;
             return DbContextManager.Create<ResetUser>().Save(user);
         }
diff --git a/Bootstrap.DataAccess/Helper/RoleHelper.cs b/Bootstrap.DataAccess/Helper/RoleHelper.cs
index 49420ac7..c18ba877 100644
--- a/Bootstrap.DataAccess/Helper/RoleHelper.cs
+++ b/Bootstrap.DataAccess/Helper/RoleHelper.cs
@@ -78,7 +78,6 @@ namespace Bootstrap.DataAccess
             var roles = new string[] { "Administrators", "Default" };
             var rs = Retrieves().Where(r => roles.Any(rl => rl.Equals(r.RoleName, StringComparison.OrdinalIgnoreCase)));
             if (rs.Any(r => r.Id == p.Id)) return true;
-            if (p.Id == string.Empty) p.Id = null;
             var ret = DbContextManager.Create<Role>().Save(p);
             if (ret) CacheCleanUtility.ClearCache(roleIds: string.IsNullOrEmpty(p.Id) ? new List<string>() : new List<string> { p.Id });
             return ret;
diff --git a/Bootstrap.DataAccess/Helper/TaskHelper.cs b/Bootstrap.DataAccess/Helper/TaskHelper.cs
index b1f64d8d..c3ab69ba 100644
--- a/Bootstrap.DataAccess/Helper/TaskHelper.cs
+++ b/Bootstrap.DataAccess/Helper/TaskHelper.cs
@@ -25,10 +25,6 @@ namespace Bootstrap.DataAccess
         /// </summary>
         /// <param name="task"></param>
         /// <returns></returns>
-        public static bool Save(Task task)
-        {
-            if (string.IsNullOrEmpty(task.Id)) task.Id = null;
-            return DbContextManager.Create<Task>().Save(task);
-        }
+        public static bool Save(Task task) => DbContextManager.Create<Task>().Save(task);
     }
 }
diff --git a/Bootstrap.DataAccess/Helper/TraceHelper.cs b/Bootstrap.DataAccess/Helper/TraceHelper.cs
index e7c5ef55..f90efc84 100644
--- a/Bootstrap.DataAccess/Helper/TraceHelper.cs
+++ b/Bootstrap.DataAccess/Helper/TraceHelper.cs
@@ -28,7 +28,6 @@ namespace Bootstrap.DataAccess
                 v.DisplayName = user.DisplayName;
                 DbContextManager.Create<Trace>().Save(new Trace
                 {
-                    Id = null,
                     Ip = v.Ip,
                     RequestUrl = v.RequestUrl,
                     LogTime = v.LastAccessTime,