The parametric data model captures an object in terms of a single tuple. This feature eliminates unnecessary self-join operations to combine tuples scattered in a temporal relation. Despite this advantage, this model is relatively difficult to implement on top of relational databases because the sizes of attributes are un-fixed. Since data boundaries are not problematic in XML, XML can be an elegant solution to implement parametric databases for temporal data. There are two approaches to implementing parametric databases using XML: 1) a native XML database with XQuery engine, and 2) an XML storage with a temporal query lan-guage. To determine which approach is appropriate in parametric databases, we consider four questions: the effectivenes...