A temporal algebra for an ER-based temporal data model

There were many temporal data models proposed in the literature. Most of them are based on relational models. Despite their popularity as design and analysis tools for information systems, ER-based temporal data models did not draw as much attention as those based on relational models did. One reason is that most ER-based temporal data models lack underlying formalism and algebra. If a conceptual model, along with an algebra, is formally defined, we can design a query language that operates on the conceptual model, not on the implementation model. Also, it can provide a basis for a user-friendly, visual query language. In this paper, we present a temporal algebra for an ER-based temporal data model called ITDM (Integrated Temporal Data Model). We define ten algebraic operations and ten temporal aggregate operations. We also define time-series specific operations.