This paper surveys the state of the art of schema inference from XML data.First

the formal models based on regular tree grammar for commonly used XML schema languages are presented.Then

the existing works on XML schema inference are summarized and compared from various aspects such as inference methods

target schema languages

supported expressiveness

regular expression types corresponding to the content models

and so on.In addition

inferences of some basic integrity constraints from XML data are also introduced.Finally

this paper points out the defects of current research and discusses some potential future research directions.This paper aims to offer a detail overview

comparison and analysis of the mainstream methods and recent progress in this field

expecting to be beneficial for subsequent research.