XTrigger: XML database trigger

摘要

An ever increasing amount of data is being exchanged and stored in the XML data format brings with it a number of advanced requirements to XML database functionality, such as trigger mechanism. Triggers are commonly used to uphold data integrity constraints and are yet to be rigorously defined for XML. To make trigger functionality for XML databases as practical and applicable as it is in the relational context, the hierarchical nature of the XML data model must be considered. However, current research on XML triggers shows clear limitations with respect to multi-document applicability and ancestor-descendant relationships. We introduce path-level granularity in combination with the novel concept of trigger scope, which plays a critical role in the validation of complex constraints. In order to effectively and efficiently support both traditional data integrity constraints and advanced semantically aware constraints, a trigger methodology that embeds several points of innovation in the context of XML triggers is hence proposed and deeply investigated in this paper.