Databases model parts of reality by containing data representing properties of real-world objects or concepts. Often, some of these properties are time-related. Thus, databases often contain data representing time-related information. However, as they may be produced by humans, such data or information may contain imperfections like uncertainties. An important purpose of databases is to allow t...

Though in most data warehousing applications no relevance is given to the time when events are recorded, some domains call for a different behavior. In particular, whenever late registrations of events take place, and particularly when the events registered are subject to further updates, the traditional design solutions fail in preserving accountability and query consistency. In this paper we ...

Though in most data warehousing applications no relevance is given to the time when events are recorded, some domains call for a different behavior. In particular, whenever late measurements of events take place, and particularly when the events registered are subject to further updates, the traditional design solutions fail in preserving accountability and query consistency. In this article, w...

In this paper we propose an indexing structure for bitemporal databases. Such structure is based on two trees, one indexing valid time and another indexing transaction time. The trees share pointers to the actual data records, which are thus not duplicated. Bitemporal queries are processed by dividing the query in two parts, a valid time part and a transaction time part. Each tree is searched a...

We present a new approach to implement an object bitempo-ral database where both valid-time and transaction-time are represented. It is based on the DataBase Version model, which allows an eecient management of object versions. This facilitates the manipulation of past events and allows a straightforward representation of branching evolution in valid-time.

A temporal database schema models objects or concepts with time-related or time-variant properties and a derived database contains measurements or descriptions concerning these temporal properties. The modelling of temporal information in a temporal database has an impact on the consistency of the database. Of course, this temporal information can be queried. In some cases, information in the q...

In data warehouses measures are analyzed along different dimensions. Although the structures of these dimensions change over time, data warehouse tools currently in use are not able to deal with these modifications in a sophisticated way. In this paper we present a bitemporal extension of the COMET metamodel. This extension enables us to represent not only the valid time of structural modificat...

In this paper, we propose a formal de nition of temporal validity which we believe is the rst and the most comprehensive quanti cation of that notion. The temporal validity is developed into the notion of sort of validity with which the confusion among various time concepts introduced for temporal databases can be dispelled. Further, we discuss the problem of preserving multiple past states of ...

Adding a temporal dimension to multimedia data is an interesting research topic, in particular with reference to the fruition of the cultural heritage. Time may be viewed either as valid-time or as transaction-time. In the rst sense, planning a virtual visit in time means working out a path that leads through the centuries taking into account the di erent historical contexts when the works of a...