On Defining Referential Integrity for XML

Referential integrity is one of the integrity constraints for any data model. In relational data model, inclusion dependency (ID) and foreign key (FK) are well studied and are widely used. In last decade, with the growing use of XML as data representation and exchange format over the web, the issue of integrity constraints in XML has received great importance to the database community. In this paper, we propose XML inclusion dependency (XID) and XML foreign key(XFK). When proposing, we show how both XID and XFK can be defined over the Document Type Definition (DTD) and are satisfied by the XML documents. We introduce a novel concept tuple that produces semantically correct values in the XML documents when satisfactions are checked. We also show that XFK is defined with the combination of XID and XML key.