【作者】 刘大昕； 张莉；

【Author】 Liu daxin Zhang Li(Harbin Engineer University 150001)

【机构】 哈尔滨工程大学计算机系；

【摘要】 本文介绍用于数据库自然语言查询接口的"类关系代数表达式"概念,类关系代数表达式与关系代数表达式基本相同,只是其中含有一些待确定的关系名,属性名,经过填充化简,类关系代数表达式转化为关系代数表达式,本文提出了填充化简规则以及将关系代数表达式转化为SQL查询命令的技术,从自然语言查询语句到类关系代数表达式的转化在另一篇文章中介绍.更多还原

【Abstract】 The concept of expressions of resembling relational algebra which can be applied to the natural language database query interface is introduced.The expressions of resembling relational algebra are basically identical to those of relational algebra,only having some relational names and attribution names to be defined.The expressions of resembling relational algebra can be converted into those of relational algebra by filling and simplifing.The thesis has given the rules of filling and simplifing and approches of converting the expressions of relational algebra into the SQ1 query commands.The convertion of the natural language query phrases to the expressions of resembling relational algebra will be introduced in another paper.更多还原