diff --git a/FreeSql.Tests/FreeSql.Tests.Provider.MySqlConnector/MySqlConnector/MySqlCodeFirstTest.cs b/FreeSql.Tests/FreeSql.Tests.Provider.MySqlConnector/MySqlConnector/MySqlCodeFirstTest.cs
index 8d279e69..cef82a4c 100644
--- a/FreeSql.Tests/FreeSql.Tests.Provider.MySqlConnector/MySqlConnector/MySqlCodeFirstTest.cs
+++ b/FreeSql.Tests/FreeSql.Tests.Provider.MySqlConnector/MySqlConnector/MySqlCodeFirstTest.cs
@@ -11,6 +11,51 @@ namespace FreeSql.Tests.MySqlConnector
 {
     public class MySqlCodeFirstTest
     {
+        [Fact]
+        public void DateTime_1()
+        {
+            var item1 = new TS_DATETIME01 { CreateTime = DateTime.Now };
+            Assert.Equal(1, g.mysql.Insert(item1).ExecuteAffrows());
+
+            var item2 = g.mysql.Select<TS_DATETIME01>().Where(a => a.Id == item1.Id).First();
+            Assert.NotNull(item2.CreateTime);
+            Assert.True(1 > Math.Abs(item2.CreateTime.Value.Subtract(item1.CreateTime.Value).TotalSeconds));
+
+            item1.CreateTime = DateTime.Now;
+            Assert.Equal(1, g.mysql.Update<TS_DATETIME01>().SetSource(item1).ExecuteAffrows());
+            item2 = g.mysql.Select<TS_DATETIME01>().Where(a => a.Id == item1.Id).First();
+            Assert.NotNull(item2.CreateTime);
+            Assert.True(1 > Math.Abs(item2.CreateTime.Value.Subtract(item1.CreateTime.Value).TotalSeconds));
+        }
+        class TS_DATETIME01
+        {
+            public Guid Id { get; set; }
+            [Column(DbType = "datetime NULL")]
+            public DateTime? CreateTime { get; set; }
+        }
+        [Fact]
+        public void DateTime_2()
+        {
+            var item1 = new TS_DATETIME02 { CreateTime = DateTime.Now };
+            Assert.Equal(1, g.mysql.Insert(item1).ExecuteAffrows());
+
+            var item2 = g.mysql.Select<TS_DATETIME02>().Where(a => a.Id == item1.Id).First();
+            Assert.NotNull(item2.CreateTime);
+            Assert.True(1 > Math.Abs(item2.CreateTime.Value.Subtract(item1.CreateTime.Value).TotalSeconds));
+
+            item1.CreateTime = DateTime.Now;
+            Assert.Equal(1, g.mysql.Update<TS_DATETIME02>().SetSource(item1).ExecuteAffrows());
+            item2 = g.mysql.Select<TS_DATETIME02>().Where(a => a.Id == item1.Id).First();
+            Assert.NotNull(item2.CreateTime);
+            Assert.True(1 > Math.Abs(item2.CreateTime.Value.Subtract(item1.CreateTime.Value).TotalSeconds));
+        }
+        class TS_DATETIME02
+        {
+            public Guid Id { get; set; }
+            [Column(DbType = "datetime NOT NULL")]
+            public DateTime? CreateTime { get; set; }
+        }
+
         [Fact]
         public void Text_StringLength_1()
         {
diff --git a/FreeSql.Tests/FreeSql.Tests/MySql/MySqlCodeFirstTest.cs b/FreeSql.Tests/FreeSql.Tests/MySql/MySqlCodeFirstTest.cs
index 463a101e..2612b4b2 100644
--- a/FreeSql.Tests/FreeSql.Tests/MySql/MySqlCodeFirstTest.cs
+++ b/FreeSql.Tests/FreeSql.Tests/MySql/MySqlCodeFirstTest.cs
@@ -11,6 +11,51 @@ namespace FreeSql.Tests.MySql
 {
     public class MySqlCodeFirstTest
     {
+        [Fact]
+        public void DateTime_1()
+        {
+            var item1 = new TS_DATETIME01 { CreateTime = DateTime.Now };
+            Assert.Equal(1, g.mysql.Insert(item1).ExecuteAffrows());
+
+            var item2 = g.mysql.Select<TS_DATETIME01>().Where(a => a.Id == item1.Id).First();
+            Assert.NotNull(item2.CreateTime);
+            Assert.True(1 > Math.Abs(item2.CreateTime.Value.Subtract(item1.CreateTime.Value).TotalSeconds));
+
+            item1.CreateTime = DateTime.Now;
+            Assert.Equal(1, g.mysql.Update<TS_DATETIME01>().SetSource(item1).ExecuteAffrows());
+            item2 = g.mysql.Select<TS_DATETIME01>().Where(a => a.Id == item1.Id).First();
+            Assert.NotNull(item2.CreateTime);
+            Assert.True(1 > Math.Abs(item2.CreateTime.Value.Subtract(item1.CreateTime.Value).TotalSeconds));
+        }
+        class TS_DATETIME01
+        {
+            public Guid Id { get; set; }
+            [Column(DbType = "datetime NULL")]
+            public DateTime? CreateTime { get; set; }
+        }
+        [Fact]
+        public void DateTime_2()
+        {
+            var item1 = new TS_DATETIME02 { CreateTime = DateTime.Now };
+            Assert.Equal(1, g.mysql.Insert(item1).ExecuteAffrows());
+
+            var item2 = g.mysql.Select<TS_DATETIME02>().Where(a => a.Id == item1.Id).First();
+            Assert.NotNull(item2.CreateTime);
+            Assert.True(1 > Math.Abs(item2.CreateTime.Value.Subtract(item1.CreateTime.Value).TotalSeconds));
+
+            item1.CreateTime = DateTime.Now;
+            Assert.Equal(1, g.mysql.Update<TS_DATETIME02>().SetSource(item1).ExecuteAffrows());
+            item2 = g.mysql.Select<TS_DATETIME02>().Where(a => a.Id == item1.Id).First();
+            Assert.NotNull(item2.CreateTime);
+            Assert.True(1 > Math.Abs(item2.CreateTime.Value.Subtract(item1.CreateTime.Value).TotalSeconds));
+        }
+        class TS_DATETIME02
+        {
+            public Guid Id { get; set; }
+            [Column(DbType = "datetime NOT NULL")]
+            public DateTime? CreateTime { get; set; }
+        }
+
         [Fact]
         public void Text_StringLength_1()
         {
diff --git a/FreeSql.Tests/FreeSql.Tests/PostgreSQL/PostgreSQLCodeFirstTest.cs b/FreeSql.Tests/FreeSql.Tests/PostgreSQL/PostgreSQLCodeFirstTest.cs
index f4ee21d6..bfb8976e 100644
--- a/FreeSql.Tests/FreeSql.Tests/PostgreSQL/PostgreSQLCodeFirstTest.cs
+++ b/FreeSql.Tests/FreeSql.Tests/PostgreSQL/PostgreSQLCodeFirstTest.cs
@@ -18,6 +18,51 @@ namespace FreeSql.Tests.PostgreSQL
 {
     public class PostgreSQLCodeFirstTest
     {
+        [Fact]
+        public void DateTime_1()
+        {
+            var item1 = new TS_DATETIME01 { CreateTime = DateTime.Now };
+            Assert.Equal(1, g.pgsql.Insert(item1).ExecuteAffrows());
+
+            var item2 = g.pgsql.Select<TS_DATETIME01>().Where(a => a.Id == item1.Id).First();
+            Assert.NotNull(item2.CreateTime);
+            Assert.True(1 > Math.Abs(item2.CreateTime.Value.Subtract(item1.CreateTime.Value).TotalSeconds));
+
+            item1.CreateTime = DateTime.Now;
+            Assert.Equal(1, g.pgsql.Update<TS_DATETIME01>().SetSource(item1).ExecuteAffrows());
+            item2 = g.pgsql.Select<TS_DATETIME01>().Where(a => a.Id == item1.Id).First();
+            Assert.NotNull(item2.CreateTime);
+            Assert.True(1 > Math.Abs(item2.CreateTime.Value.Subtract(item1.CreateTime.Value).TotalSeconds));
+        }
+        class TS_DATETIME01
+        {
+            public Guid Id { get; set; }
+            [Column(DbType = "timestamp NULL")]
+            public DateTime? CreateTime { get; set; }
+        }
+        [Fact]
+        public void DateTime_2()
+        {
+            var item1 = new TS_DATETIME02 { CreateTime = DateTime.Now };
+            Assert.Equal(1, g.pgsql.Insert(item1).ExecuteAffrows());
+
+            var item2 = g.pgsql.Select<TS_DATETIME02>().Where(a => a.Id == item1.Id).First();
+            Assert.NotNull(item2.CreateTime);
+            Assert.True(1 > Math.Abs(item2.CreateTime.Value.Subtract(item1.CreateTime.Value).TotalSeconds));
+
+            item1.CreateTime = DateTime.Now;
+            Assert.Equal(1, g.pgsql.Update<TS_DATETIME02>().SetSource(item1).ExecuteAffrows());
+            item2 = g.pgsql.Select<TS_DATETIME02>().Where(a => a.Id == item1.Id).First();
+            Assert.NotNull(item2.CreateTime);
+            Assert.True(1 > Math.Abs(item2.CreateTime.Value.Subtract(item1.CreateTime.Value).TotalSeconds));
+        }
+        class TS_DATETIME02
+        {
+            public Guid Id { get; set; }
+            [Column(DbType = "timestamp NOT NULL")]
+            public DateTime? CreateTime { get; set; }
+        }
+
         [Fact]
         public void Blob()
         {
diff --git a/FreeSql/Internal/UtilsExpressionTree.cs b/FreeSql/Internal/UtilsExpressionTree.cs
index 24aeb1f8..42b027d0 100644
--- a/FreeSql/Internal/UtilsExpressionTree.cs
+++ b/FreeSql/Internal/UtilsExpressionTree.cs
@@ -453,12 +453,12 @@ namespace FreeSql.Internal
             foreach (var col in trytb.Primarys)
             {
                 col.Attribute.IsNullable = false;
-                col.Attribute.DbType = col.Attribute.DbType.Replace("NOT NULL", "").Trim();
+                col.Attribute.DbType = col.Attribute.DbType.Replace("NOT NULL", "").Replace(" NULL", "").Trim();
             }
             foreach (var col in trytb.Columns.Values)
             {
                 var ltp = @"\(([^\)]+)\)";
-                col.DbTypeText = Regex.Replace(col.Attribute.DbType.Replace("NOT NULL", "").Trim(), ltp, "");
+                col.DbTypeText = Regex.Replace(col.Attribute.DbType.Replace("NOT NULL", "").Replace(" NULL", "").Trim(), ltp, "");
                 var m = Regex.Match(col.Attribute.DbType, ltp);
                 if (m.Success == false) continue;
                 var sizeStr = m.Groups[1].Value.Trim();
@@ -884,7 +884,7 @@ namespace FreeSql.Internal
                             foreach (var col in tbmid.Primarys)
                             {
                                 col.Attribute.IsNullable = false;
-                                col.Attribute.DbType = col.Attribute.DbType.Replace("NOT NULL", "").Trim();
+                                col.Attribute.DbType = col.Attribute.DbType.Replace("NOT NULL", "").Replace(" NULL", "").Trim();
                             }
                         }
                     }
diff --git a/Providers/FreeSql.Provider.Oracle/OracleUtils.cs b/Providers/FreeSql.Provider.Oracle/OracleUtils.cs
index c6eaca38..4538a0ff 100644
--- a/Providers/FreeSql.Provider.Oracle/OracleUtils.cs
+++ b/Providers/FreeSql.Provider.Oracle/OracleUtils.cs
@@ -28,7 +28,7 @@ namespace FreeSql.Oracle
             var ret = new OracleParameter { ParameterName = QuoteParamterName(parameterName), OracleDbType = dbtype, Value = value };
             if (col != null)
             {
-                var dbtype2 = (OracleDbType)_orm.DbFirst.GetDbType(new DatabaseModel.DbColumnInfo { DbTypeTextFull = col.Attribute.DbType.Replace("NOT NULL", "").Trim(), DbTypeText = col.DbTypeText });
+                var dbtype2 = (OracleDbType)_orm.DbFirst.GetDbType(new DatabaseModel.DbColumnInfo { DbTypeTextFull = col.Attribute.DbType.Replace("NOT NULL", "").Replace(" NULL", "").Trim(), DbTypeText = col.DbTypeText });
                 switch (dbtype2)
                 {
                     case OracleDbType.Char: