Course Contents Time is ubiquitous in information systems. Almost every enterprise faces the problem of its data becoming out of date. However, such data is often valuable, so it should be archived and some means to access it should be provided. Also, some data may be inherently historical, e.g., medical, cadastral, or judicial records.
Temporal databases provide a uniform and systematic way of dealing with historical data.
In our presentation we concentrate on possible ways of extending the standard relational model with new a-priori interpreted data types in a clean and natural way. In the context of temporal databases we are mostly interested in the type of linearly ordered set of time instants that represents the flow of time. We discuss the necessary extensions to the original model needed to accommodate the new functionality. We also give an overview of the developments in the area of temporal databases with an emphasis on relating the various proposed models to our precise abstract model based on logic.