【摘要】 Twig模式最小化作为XML查询优化的一个重要方面,由于在进行最小化的过程中通常要利用XML Schema中的约束信息,因此被称为Schema特征。为了简化运用传统方法提取Schema特征的过程,以及确保提取过程的正确性,提出了一种自动提取Schema特征的模型检查算法。在Schema的形式模型的基础上,利用扩展的CTL公式表示Schema特征,提出算法以检查Schema模型是否满足要求的特征。由于扩展了CTL公式,所提算法不但可以检查孩子、子孙等前向的Schema特征,而且可以检查双亲、祖先等后向特征。最后,实现了支持该算法的模型检查器。更多还原

【Abstract】 As an important aspect of XML query optimization-Twig pattern minimizing,usually needs to take advantage of the constraints of XML Schema during the minimization process,so it is called Schema features.To simplify the traditional methods of extracting Schema features,and to ensure the accuracy of the extraction process,we proposed a model-checking algorithm to extract XML Schema features automatically.Based on the formal model of an XML Schema,we used an extended CTL formula to express Schema features,and proposed an algorithm to check if an XML Schema model satisfies CTL formula.Due to the expansion of CTL formulas,the proposed algorithm can not only express the prior Schema features,but also represent parents,ancestors and other backward features.Finally,we realizaed a aids tool for our methods.更多还原