diff --git a/FreeSql/DataAnnotations/ColumnFluent.cs b/FreeSql/DataAnnotations/ColumnFluent.cs
index 7b6ae7f2..e7b8bd2e 100644
--- a/FreeSql/DataAnnotations/ColumnFluent.cs
+++ b/FreeSql/DataAnnotations/ColumnFluent.cs
@@ -55,5 +55,12 @@
 			_column.IsIgnore = value;
 			return this;
 		}
+		/// <summary>
+		/// 乐观锁
+		/// </summary>
+		public ColumnFluent IsVersion(bool value) {
+			_column.IsVersion = value;
+			return this;
+		}
 	}
 }
diff --git a/FreeSql/Extensions/EntityUtilExtensions.cs b/FreeSql/Extensions/EntityUtilExtensions.cs
index 8e8acde7..39061994 100644
--- a/FreeSql/Extensions/EntityUtilExtensions.cs
+++ b/FreeSql/Extensions/EntityUtilExtensions.cs
@@ -53,12 +53,28 @@ namespace FreeSql.Extensions.EntityUtil {
 							}.Where(c => c != null).ToArray()
 						);
 					}
-					exps.Add(
-						Expression.IfThen(
-							Expression.IsFalse(var3IsNull),
-							Expression.IfThenElse(
-								Expression.Equal(Expression.MakeMemberAccess(var1Parm, _table.Properties[pks[a].CsName]), Expression.Default(pks[a].CsType)),
-								expthen,
+					if (pks[a].Attribute.IsIdentity || isguid || pks[a].CsType == typeof(string) || pks[a].CsType.IsNullableType()) {
+						exps.Add(
+							Expression.IfThen(
+								Expression.IsFalse(var3IsNull),
+								Expression.IfThenElse(
+									Expression.Equal(Expression.MakeMemberAccess(var1Parm, _table.Properties[pks[a].CsName]), Expression.Default(pks[a].CsType)),
+									expthen,
+									Expression.Block(
+										new Expression[]{
+											a > 0 ? Expression.Call(var2Sb, MethodStringBuilderAppend, Expression.Constant(splitString)) : null,
+											Expression.Call(var2Sb, MethodStringBuilderAppend,
+												Expression.Convert(Expression.MakeMemberAccess(var1Parm, _table.Properties[pks[a].CsName]), typeof(object))
+											)
+										}.Where(c => c != null).ToArray()
+									)
+								)
+							)
+						);
+					} else {
+						exps.Add(
+							Expression.IfThen(
+								Expression.IsFalse(var3IsNull),
 								Expression.Block(
 									new Expression[]{
 										a > 0 ? Expression.Call(var2Sb, MethodStringBuilderAppend, Expression.Constant(splitString)) : null,
@@ -68,8 +84,8 @@ namespace FreeSql.Extensions.EntityUtil {
 									}.Where(c => c != null).ToArray()
 								)
 							)
-						)
-					);
+						);
+					}
 				}
 				exps.Add(
 					Expression.IfThen(
diff --git a/readme.md b/readme.md
index 7f609fa4..997db2ce 100644
--- a/readme.md
+++ b/readme.md
@@ -4,7 +4,7 @@ FreeSql 是一个功能强大的 .NETStandard 库，用于对象关系映射程
 |--------------|  ------- |  ---- |
 | FreeSql | [![nuget](https://img.shields.io/nuget/v/FreeSql.svg?style=flat-square)](https://www.nuget.org/packages/FreeSql) | [![stats](https://img.shields.io/nuget/dt/FreeSql.svg?style=flat-square)](https://www.nuget.org/stats/packages/FreeSql?groupby=Version) |
 | [FreeSql.Repository](https://github.com/2881099/FreeSql/wiki/Repository) | [![nuget](https://img.shields.io/nuget/v/FreeSql.Repository.svg?style=flat-square)](https://www.nuget.org/packages/FreeSql.Repository) | [![stats](https://img.shields.io/nuget/dt/FreeSql.Repository.svg?style=flat-square)](https://www.nuget.org/stats/packages/FreeSql.Repository?groupby=Version) |
-| [FreeSql.DbContext](https://github.com/2881099/FreeSql/wiki/DbContext) | [![nuget](https://img.shields.io/nuget/v/FreeSql.DbContext.svg?style=flat-square)](https://www.nuget.org/packages/FreeSql.DbContext) | [![stats](https://img.shields.io/nuget/dt/FreeSql.DbContext.svg?style=flat-square)](https://www.nuget.org/stats/packages/FreeSql.DbContext?groupby=Version) |
+| [FreeSql.DbContext](https://github.com/2881099/FreeSql.DbContext) | [![nuget](https://img.shields.io/nuget/v/FreeSql.DbContext.svg?style=flat-square)](https://www.nuget.org/packages/FreeSql.DbContext) | [![stats](https://img.shields.io/nuget/dt/FreeSql.DbContext.svg?style=flat-square)](https://www.nuget.org/stats/packages/FreeSql.DbContext?groupby=Version) |
 
 # 特性