diff --git a/FreeSql.DbContext/FreeSql.DbContext.xml b/FreeSql.DbContext/FreeSql.DbContext.xml
index e76e3740..65c54b71 100644
--- a/FreeSql.DbContext/FreeSql.DbContext.xml
+++ b/FreeSql.DbContext/FreeSql.DbContext.xml
@@ -125,13 +125,6 @@
             清空状态数据
             </summary>
         </member>
-        <member name="M:FreeSql.DbSet`1.RemoveAsync(System.Linq.Expressions.Expression{System.Func{`0,System.Boolean}})">
-            <summary>
-            根据 lambda 条件删除数据
-            </summary>
-            <param name="predicate"></param>
-            <returns></returns>
-        </member>
         <member name="M:FreeSql.DbSet`1.Add(`0)">
             <summary>
             添加
@@ -520,14 +513,5 @@
             <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.Tests/FreeSql.Tests/UnitTest3.cs b/FreeSql.Tests/FreeSql.Tests/UnitTest3.cs
index c8761dff..1f93eca1 100644
--- a/FreeSql.Tests/FreeSql.Tests/UnitTest3.cs
+++ b/FreeSql.Tests/FreeSql.Tests/UnitTest3.cs
@@ -156,9 +156,23 @@ namespace FreeSql.Tests
             }
         }
 
+        class testInsertNullable
+        {
+            [Column(IsIdentity = true)]
+            public long Id { get; set; }
+
+            [Column(IsNullable = false)]
+            public string str1 { get; set; }
+            [Column(IsNullable = false)]
+            public int? int1 { get; set; }
+        }
+
         [Fact]
         public void Test03()
         {
+            g.sqlite.Insert(new testInsertNullable()).NoneParameter().ExecuteAffrows();
+
+
             var sqlxx = g.pgsql.InsertOrUpdate<userinfo>().SetSource(new userinfo { userid = 10 }).UpdateColumns(a => new { a.birthday, a.CardNo }).ToSql();
 
             var aff1 = g.sqlite.GetRepository<Edi, long>().Delete(10086);
diff --git a/FreeSql/Internal/CommonProvider/InsertProvider.cs b/FreeSql/Internal/CommonProvider/InsertProvider.cs
index 3abd94b2..6275a822 100644
--- a/FreeSql/Internal/CommonProvider/InsertProvider.cs
+++ b/FreeSql/Internal/CommonProvider/InsertProvider.cs
@@ -548,7 +548,7 @@ namespace FreeSql.Internal.CommonProvider
                     else
                     {
                         object val = col.GetMapValue(d);
-                        if (val == null && col.Attribute.IsNullable == false) val = Utils.GetDataReaderValue(col.CsType.NullableTypeOrThis(), null);//#384
+                        if (val == null && col.Attribute.IsNullable == false) val = col.CsType == typeof(string) ? "" : Utils.GetDataReaderValue(col.CsType.NullableTypeOrThis(), null);//#384
                         if (_noneParameter)
                             sb.Append(_commonUtils.GetNoneParamaterSqlValue(specialParams, col.Attribute.MapType, val));
                         else
diff --git a/Providers/FreeSql.Provider.Dameng/Curd/DamengInsert.cs b/Providers/FreeSql.Provider.Dameng/Curd/DamengInsert.cs
index 643da775..2bee3fba 100644
--- a/Providers/FreeSql.Provider.Dameng/Curd/DamengInsert.cs
+++ b/Providers/FreeSql.Provider.Dameng/Curd/DamengInsert.cs
@@ -67,7 +67,7 @@ namespace FreeSql.Dameng.Curd
                     else
                     {
                         object val = col.GetMapValue(d);
-                        if (val == null && col.Attribute.IsNullable == false) val = Utils.GetDataReaderValue(col.CsType.NullableTypeOrThis(), null);//#384
+                        if (val == null && col.Attribute.IsNullable == false) val = col.CsType == typeof(string) ? "" : Utils.GetDataReaderValue(col.CsType.NullableTypeOrThis(), null);//#384
                         if (_noneParameter)
                             sb.Append(_commonUtils.GetNoneParamaterSqlValue(specialParams, col.Attribute.MapType, val));
                         else
diff --git a/Providers/FreeSql.Provider.Odbc/Dameng/Curd/OdbcDamengInsert.cs b/Providers/FreeSql.Provider.Odbc/Dameng/Curd/OdbcDamengInsert.cs
index da81f57b..de1f043d 100644
--- a/Providers/FreeSql.Provider.Odbc/Dameng/Curd/OdbcDamengInsert.cs
+++ b/Providers/FreeSql.Provider.Odbc/Dameng/Curd/OdbcDamengInsert.cs
@@ -67,7 +67,7 @@ namespace FreeSql.Odbc.Dameng
                     else
                     {
                         object val = col.GetMapValue(d);
-                        if (val == null && col.Attribute.IsNullable == false) val = Utils.GetDataReaderValue(col.CsType.NullableTypeOrThis(), null);//#384
+                        if (val == null && col.Attribute.IsNullable == false) val = col.CsType == typeof(string) ? "" : Utils.GetDataReaderValue(col.CsType.NullableTypeOrThis(), null);//#384
                         if (_noneParameter)
                             sb.Append(_commonUtils.GetNoneParamaterSqlValue(specialParams, col.Attribute.MapType, val));
                         else
diff --git a/Providers/FreeSql.Provider.Odbc/Oracle/Curd/OdbcOracleInsert.cs b/Providers/FreeSql.Provider.Odbc/Oracle/Curd/OdbcOracleInsert.cs
index cb49ddf8..f4ea0596 100644
--- a/Providers/FreeSql.Provider.Odbc/Oracle/Curd/OdbcOracleInsert.cs
+++ b/Providers/FreeSql.Provider.Odbc/Oracle/Curd/OdbcOracleInsert.cs
@@ -67,7 +67,7 @@ namespace FreeSql.Odbc.Oracle
                     else
                     {
                         object val = col.GetMapValue(d);
-                        if (val == null && col.Attribute.IsNullable == false) val = Utils.GetDataReaderValue(col.CsType.NullableTypeOrThis(), null);//#384
+                        if (val == null && col.Attribute.IsNullable == false) val = col.CsType == typeof(string) ? "" : Utils.GetDataReaderValue(col.CsType.NullableTypeOrThis(), null);//#384
                         if (_noneParameter)
                             sb.Append(_commonUtils.GetNoneParamaterSqlValue(specialParams, col.Attribute.MapType, val));
                         else
diff --git a/Providers/FreeSql.Provider.Oracle/Curd/OracleInsert.cs b/Providers/FreeSql.Provider.Oracle/Curd/OracleInsert.cs
index 98117dc5..371191d9 100644
--- a/Providers/FreeSql.Provider.Oracle/Curd/OracleInsert.cs
+++ b/Providers/FreeSql.Provider.Oracle/Curd/OracleInsert.cs
@@ -69,7 +69,7 @@ namespace FreeSql.Oracle.Curd
                     else
                     {
                         object val = col.GetMapValue(d);
-                        if (val == null && col.Attribute.IsNullable == false) val = Utils.GetDataReaderValue(col.CsType.NullableTypeOrThis(), null);//#384
+                        if (val == null && col.Attribute.IsNullable == false) val = col.CsType == typeof(string) ? "" : Utils.GetDataReaderValue(col.CsType.NullableTypeOrThis(), null);//#384
                         if (_noneParameter)
                             sb.Append(_commonUtils.GetNoneParamaterSqlValue(specialParams, col.Attribute.MapType, val));
                         else