1994 ◽  
Vol 6 (4) ◽  
pp. 572-586 ◽  
Author(s):  
M. Gyssens ◽  
J. Paredaens ◽  
J. van den Bussche ◽  
D. van Gucht

1988 ◽  
Vol 23 (11) ◽  
pp. 164-175 ◽  
Author(s):  
David Beech

2005 ◽  
Vol 10 (5) ◽  
pp. 59-94
Author(s):  
Deja Hepziba Francis ◽  
Sanjay Madria ◽  
Chaman Sabharwal

1980 ◽  
Vol 3 (3) ◽  
pp. 363-377
Author(s):  
John Grant

In this paper we investigate the inclusion of incomplete information in the relational database model. This is done by allowing nonatomic entries, i.e. sets, as elements in the database. A nonatomic entry is interpreted as a set of possible elements, one of which is the correct one. We deal primarily with numerical entries where an allowed set is an interval, and character string entries. We discuss the various operations of the relational algebra as well as the notion of functional dependency for the database model.


2003 ◽  
Vol 1836 (1) ◽  
pp. 118-125 ◽  
Author(s):  
Bo Huang ◽  
Li Yao

Dynamic segmentation is viewed as one of the most important functions of geographic information systems for transportation applications. Although the road network and associated events (e.g., pavement material, traffic volume, incidents) can be referenced to both space and time, the spatial and temporal dimensions have not been well integrated. Modeling space-varying, time-varying, and space-time-varying events in dynamic segmentation by using an object database approach that is in line with the Object Database Management Group standard is explored. A mechanism called parametric polymorphism is used to lift conventional data types to spatial, temporal, and spatiotemporal types for maintaining knowledge about events that could change spatially, temporally, and spatiotemporally along linear features. An associated object query language, DS-OQL, was designed to support the formulation of spatial, temporal, and spatiotemporal queries on the road and event information.


2011 ◽  
Vol 22 (1) ◽  
pp. 25-42 ◽  
Author(s):  
MICHAEL JOHNSON ◽  
ROBERT ROSEBRUGH ◽  
R. J. WOOD

This paper extends the ‘lens’ concept for view updating in Computer Science beyond the categories of sets and ordered sets. It is first shown that a constant complement view updating strategy also corresponds to a lens for a categorical database model. A variation on the lens concept called a c-lens is introduced, and shown to correspond to the categorical notion of Grothendieck opfibration. This variant guarantees a universal solution to the view update problem for functorial update processes.


Sign in / Sign up

Export Citation Format

Share Document