Graphical environment for change detection in structured documents

Change detection in structured documents (e.g. SGML) is important in many applications including data warehousing, digital libraries and Internet databases. This paper presents a graphical environment for detecting changes in the structured documents. We represent each document by an ordered labeled tree based on the underlying markup language. We then compare two documents by using previously developed algorithms for pattern matching and pattern discovery in trees. Several operators are developed to support the comparison of the documents; graphical devices are provided to facilitate the use of the operators. We believe the proposed tool is useful for not only document management, but also software maintenance, particularly configuration management and version control, where programs are represented as parse trees and detecting changes in the trees provides a way to find the syntactic differences of two program versions.