Abstract

Large parts of today’s data is stored in text documents that undergo a series of changes during their lifetime. For instance during the development of a software product the source code changes frequently. Currently, managing such data relies on version control systems (VCSs). Extracting information from large documents and their different versions is a manual and tedious process. We present Qvestor, a system that allows to declaratively query documents. It leverages information about the structure of a document that is available as a context-free grammar and allows to declaratively query document versions through a grammar annotated with relational algebra expressions. We define and illustrate the annotation of grammars with relational algebra expressions and show how to translate the annotations to easy to use SQL views.