Add attribute propertty IsOnlyIgnoreUpdate

Src/Asp.Net/SqlServerTest/UnitTest/UQueryable.cs

@@ -38,6 +38,20 @@ namespace OrmTest
                Dc=it.Int
             }).ToSql().Key;
             UValidate.Check(sql, "SELECT  [Dc] AS [DcNull] , [Int] AS [Dc]  FROM [UnitSelectTest]", "Queryable");
+
+            sql= Db.Updateable<UnitSelectTest2>(new UnitSelectTest2()).ToSql().Key;
+        }
+
+
+
+        public class UnitSelectTest2
+        {
+            [SqlSugar.SugarColumn(IsOnlyIgnoreUpdate = true)]
+            public decimal? DcNull { get; set; }
+            public decimal Dc { get; set; }
+            public int? IntNull { get; set; }
+            [SqlSugar.SugarColumn(IsPrimaryKey = true)]
+            public decimal Int { get; set; }
         }
 
         public class UnitSelectTest

Src/Asp.Net/SqlServerTest/UnitTest/UValidate.cs

@@ -10,7 +10,7 @@ namespace OrmTest
     {
         public static void Check(object a, object b, object name)
         {
-            if (a?.ToString() != b?.ToString())
+            if (a?.ToString()?.Trim() != b?.ToString()?.Trim())
             {
                 throw new Exception(name + " error");
             }

Src/Asp.Net/SqlSugar/Abstract/EntityMaintenance/EntityMaintenance.cs

@@ -173,6 +173,7 @@ namespace SqlSugar
                         column.NoSerialize = sugarColumn.NoSerialize;
                         column.DefaultValue = sugarColumn.DefaultValue;
                         column.IndexGroupNameList = sugarColumn.IndexGroupNameList;
+                        column.IsOnlyIgnoreUpdate = sugarColumn.IsOnlyIgnoreUpdate;
                     }
                     else
                     {

Src/Asp.Net/SqlSugar/Abstract/SugarProvider/SqlSugarAccessory.cs

@@ -291,6 +291,11 @@ namespace SqlSugar
             sqlBuilder.UpdateBuilder.LambdaExpressions = InstanceFactory.GetLambdaExpressions(this.CurrentConnectionConfig);
             sqlBuilder.Context = result.SqlBuilder.UpdateBuilder.Context = this;
             result.Init();
+            var ignoreColumns = result.EntityInfo.Columns.Where(it => it.IsOnlyIgnoreUpdate).ToList();
+            if (ignoreColumns!=null&&ignoreColumns.Any())
+            {
+                result = (UpdateableProvider<T>)result.IgnoreColumns(ignoreColumns.Select(it=>it.PropertyName).ToArray());
+            }
             return result;
         }
 

Src/Asp.Net/SqlSugar/Entities/EntityColumnInfo.cs

@@ -27,6 +27,7 @@ namespace SqlSugar
         public int DecimalDigits { get; set; }
         public string OracleSequenceName { get; set; }
         public bool IsOnlyIgnoreInsert { get; set; }
+        public bool IsOnlyIgnoreUpdate { get; set; }
         public bool IsTranscoding { get; set; }
         public string SerializeDateTimeFormat { get;  set; }
         public bool IsJson { get;  set; }

Src/Asp.Net/SqlSugar/Entities/Mapping/SugarMappingAttribute.cs

@@ -112,6 +112,13 @@ namespace SqlSugar
             set { _IsOnlyIgnoreInsert = value; }
         }
 
+        private bool _IsOnlyIgnoreUpdate;
+        public bool IsOnlyIgnoreUpdate
+        {
+            get { return _IsOnlyIgnoreUpdate; }
+            set { _IsOnlyIgnoreUpdate = value; }
+        }
+
 
         private bool _IsEnableUpdateVersionValidation;
         public bool IsEnableUpdateVersionValidation {