比如，最初曾经尝试将XML数据保存在关系数据库的varchar2字段中，然后简单地增加一个XQuery引擎层，结果查询性能很差。

For example, early attempts at storing XML data in varchar2 fields of a relational database resulted in poor query performance when an XQuery engine was simply layered on top.

youdao

比如，最初曾经尝试将XML数据保存在关系数据库的varchar2字段中，然后简单地增加一个XQuery引擎层，结果查询性能很差。

For example, early attempts at storing XML data in varchar2 fields of a relational database resulted in poor query performance when an XQuery engine was simply layered on top.

youdao