关键词: 空值，XML，概率数据库，N次矩运算

Abstract: Uncertainty and Incompleteness are a real-world challenges of the database. The combination of NULL value and probabilistic XML database can better deal with data, but also increase the complexity of the database. We proposed two interpretation what means the null value in the XML probabilistic database, one of them can generate probabilistic interval,so we presented a compromise solution to the probabilistic interval problem in probabilistic XML database with NULL value. Finally, we proposed an Nth moment method for anglicizing probabilistic database comprehensively.

Key words: Null value, XML, Probabilistic database, Nth moment operation