/// <summary>
        /// 拷贝构造函数
        /// </summary>
        /// <param name="toCopy">To copy.</param>
        public RowPutChange(RowPutChange toCopy) : base(toCopy.TableName, toCopy.GetPrimaryKey())
        {
            if (toCopy.timestamp.HasValue)
            {
                timestamp = toCopy.timestamp;
            }

            columnsToPut.AddRange(toCopy.columnsToPut);
        }
        /// <summary>
        /// 添加一个Put操作
        /// </summary>
        /// <param name="condition">检查条件</param>
        /// <param name="primaryKey">主键</param>
        /// <param name="attributeColumns">属性</param>
        public void AddPut(Condition condition, PrimaryKey primaryKey, AttributeColumns attributeColumns)
        {
            var item = new RowPutChange(TableName, primaryKey)
            {
                Condition = condition
            };

            if (attributeColumns != null)
            {
                foreach (var column in attributeColumns)
                {
                    item.AddColumn(column.Key, column.Value);
                }
            }

            RowPutChanges.Add(item);
        }