diff --git a/FreeSql.DbContext/FreeSql.DbContext.xml b/FreeSql.DbContext/FreeSql.DbContext.xml
index 9c6cd88b..743835e4 100644
--- a/FreeSql.DbContext/FreeSql.DbContext.xml
+++ b/FreeSql.DbContext/FreeSql.DbContext.xml
@@ -532,5 +532,14 @@
             <param name="that"></param>
             <returns></returns>
         </member>
+        <member name="M:Microsoft.Extensions.DependencyInjection.FreeSqlRepositoryDependencyInjection.AddFreeRepository(Microsoft.Extensions.DependencyInjection.IServiceCollection,System.Action{FreeSql.FluentDataFilter},System.Reflection.Assembly[])">
+            <summary>
+            批量注入 Repository，可以参考代码自行调整
+            </summary>
+            <param name="services"></param>
+            <param name="globalDataFilter"></param>
+            <param name="assemblies"></param>
+            <returns></returns>
+        </member>
     </members>
 </doc>
diff --git a/FreeSql/Internal/CommonProvider/InsertOrUpdateProvider.cs b/FreeSql/Internal/CommonProvider/InsertOrUpdateProvider.cs
index 1d8a13c4..92c5b536 100644
--- a/FreeSql/Internal/CommonProvider/InsertOrUpdateProvider.cs
+++ b/FreeSql/Internal/CommonProvider/InsertOrUpdateProvider.cs
@@ -92,6 +92,8 @@ namespace FreeSql.Internal.CommonProvider
                     if (changedDict != null && changedDict.ContainsKey(col.Attribute.Name) == false)
                         changedDict.Add(col.Attribute.Name, true);
                 }
+                if (val == null && col.Attribute.MapType == typeof(string) && col.Attribute.IsNullable == false)
+                    col.SetValue(data, val = "");
             }
         }
 
diff --git a/FreeSql/Internal/CommonProvider/InsertProvider.cs b/FreeSql/Internal/CommonProvider/InsertProvider.cs
index 30495e56..1d394457 100644
--- a/FreeSql/Internal/CommonProvider/InsertProvider.cs
+++ b/FreeSql/Internal/CommonProvider/InsertProvider.cs
@@ -171,6 +171,8 @@ namespace FreeSql.Internal.CommonProvider
                             col.SetValue(data, val = FreeUtil.NewMongodbId());
                     }
                 }
+                if (val == null && col.Attribute.MapType == typeof(string) && col.Attribute.IsNullable == false)
+                    col.SetValue(data, val = "");
             }
         }
 
diff --git a/FreeSql/Internal/CommonProvider/UpdateProvider.cs b/FreeSql/Internal/CommonProvider/UpdateProvider.cs
index b6a24926..1de0b502 100644
--- a/FreeSql/Internal/CommonProvider/UpdateProvider.cs
+++ b/FreeSql/Internal/CommonProvider/UpdateProvider.cs
@@ -359,6 +359,8 @@ namespace FreeSql.Internal.CommonProvider
                         if (changedDict != null && changedDict.ContainsKey(col.Attribute.Name) == false)
                             changedDict.Add(col.Attribute.Name, true);
                     }
+                    if (val == null && col.Attribute.MapType == typeof(string) && col.Attribute.IsNullable == false)
+                        col.SetValue(data, val = "");
                 }
             }
         }
@@ -379,6 +381,8 @@ namespace FreeSql.Internal.CommonProvider
                     if (changedDict != null && changedDict.ContainsKey(col.Attribute.Name) == false)
                         changedDict.Add(col.Attribute.Name, true);
                 }
+                if (val == null && col.Attribute.MapType == typeof(string) && col.Attribute.IsNullable == false)
+                    col.SetValue(data, val = "");
             }
         }