In a relational language, such a query would require a join that might span several data tables and system catalog tables.
而在关系语言中，这种查询需要进行也许跨越了多个数据表和系统目录表的联接。
The result is likely to be a language with a more complex semantic definition than that of a relational language such as SQL.
其结果很可能产生其语义定义比关系语言(如sql)更加复杂的一门语言。
It also requires a query language to provide constructors that are capable of creating complex nested structures on the fly — a facility that is not needed in a relational language.
这也需要一种查询语言来提供可动态创建复杂嵌套结构的构造函数，而该工具在关系语言中是不需要的。
It also requires a query language to provide constructors that are capable of creating complex nested structures on the fly — a facility that is not needed in a relational language.
这也需要一种查询语言来提供可动态创建复杂嵌套结构的构造函数，而该工具在关系语言中是不需要的。
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