XML functional dependencies based on tree homomorphisms [Elektronische Ressource] / Diem-Thu Trinh

XML Functional Dependenciesbased on Tree HomomorphismsDoctoral ThesisPresented in partial fulfilment of the requirements for the degree ofDoctor rerum naturalium (Dr. rer. nat.)at theFaculty of Mathematics/Informatics and Mechanical Engineering,Clausthal University of TechnologyDiem-Thu TrinhJune 2009Supervisor: Prof. Dr. Sven HartmannCo-Supervisor: Prof. Dr. Sebastian Link (Victoria University of Wellington)Date of the Oral Examination: July 3, 2009Chairman of the Board of Examiners: Prof. Dr. Ju¨rgen DixAbstractFunctional dependencies form an important class of integrity constraints whichhasbeenwellstudiedinthecontextofrelationaldatabases. Recently, theeXten-sible Markup Language (XML) has emerged as a popular and flexible standardfor modelling and managing data in a variety of domains. Although several at-tempts have been made to generalise the concept of functional dependencies tothe context of XML, the search for an interesting yet practical formalisation ofXML functional dependencies still poses a challenge.In this dissertation I propose and investigate a new class of XML functionaldependencies with properties (called pXFDs) defined on the basis of tree homo-morphism. My first contribution is to demonstrate that one can reason aboutpXFDs efficiently.