Versus Concrete Temporal Query Languages Jan Chomicki, University at Buffalo, USA, http://www.cse.buffalo.edu/~chomicki David Toman, University of Waterloo, Canada, http://www.cs.uwaterloo.ca/~david SYNONYMS historical query languages DEFINITION Temporal query languages are a family of query languages designed to query (and access in general) time-dependent information stored in temporal databa...

Storage costs are rapidly decreasing, making it feasible to store larger amounts of data in databases. This also makes it possible to store previous versions of data in the databases, instead of only keeping the last version. Recently, the amount of data available in XML has been rapidly increasing. In this paper, we describe TeXOR, a temporal XML database system built on top of an object-relat...

Based on a systematic study of the semantics of temporal attributes of entities, this paper provides new guidelines for the design of temporal relational databases. The notions of observation and update patterns of an attribute capture when the attribute changes value and when the changes are recorded in the database. A lifespan describes when an attribute has a value. And derivation functions ...

Time is one of the most difficult aspects to handle in real world applications such as database systems. Relational database management systems proposed by Codd offer very little built-in query language support for temporal data management. The model itself incorporates neither the concept of time nor any theory of temporal semantics. Many temporal extensions of the relational model have been p...

The design of appropriate database schemas is critical to the effective use of database technology and the construction of effective information systems that exploit this technology. The temporal aspects of database schemas are often particularly complex and thus difficult and error-prone to design. This chapter focuses on the temporal aspects of database schemas. Its contributions are twofold....

This paper addresses the issue of visual query formulation for temporal databases. We introduce a number of visual constructs that allow users to build queries in a modular fashion based on a temporal Extended Entity{Relationship Model. These constructs are: Temporal projection, temporal selection, time links, ltering and set operators, and temporal aggregates.

Present paper is devoted to information security issues in temporal databases. All features and characteristics of temporal systems are considered and studied in this paper: main important types of temporal relations; as well as the principles providingconfidentiality, integrity, and reliability the three basic components of information security in databases. The presented examples in this pape...

Geographical (spatial) information about the real world changes rapidly with time. We can simply see examples of these changes when we look at any area. New buildings, new roads and highways, and many other new constructions are added or updated. Spatial changes can be categorized in two categories: (1) Discrete: changes of the geometries of physical entities (i.e., buildings) and (2) abstract:...

This paper introduces a model of spatio-temporal database that we are developing to query interesting events in video sequences. The database that we are designing is pushing the state of the art for a number of elds, and there are many issues that are still waiting a satisfactory solution. In this paper we present our (albeit still partial) answer to some of these problems, and the future dire...

Aggregate computation, such as selecting the minimum attribute value of a relation, is expensive, especially in a temporal database. We describe the basic techniques behind computing aggregates in conventional databases and show that these techniques are not efficient when applied to temporal databases. We examine the problem of computing constant intervals (intervals of time for which the aggr...