public RowUpdateChange(RowUpdateChange toCopy) : base(toCopy.TableName, toCopy.PrimaryKey)
        {
            if (toCopy.timestamp.HasValue)
            {
                timestamp = toCopy.timestamp;
            }

            columnsToUpdate.AddRange(toCopy.columnsToUpdate);
        }
        /// <summary>
        /// 添加一个Update操作
        /// </summary>
        /// <param name="condition"></param>
        /// <param name="primaryKey"></param>
        /// <param name="updateAttributes"></param>
        public void AddUpdate(Condition condition, PrimaryKey primaryKey, UpdateOfAttribute updateAttributes)
        {
            var item = new RowUpdateChange(TableName, primaryKey)
            {
                Condition = condition
            };

            item.FromUpdateOfAtrribute(updateAttributes);

            RowUpdateChanges.Add(item);
        }