Showing papers by "Ramez Elmasri published in 1996"

Efficient temporal join processing using time index

Abstract: Time is an attribute of all real-world phenomena and many real-world database applications naturally involve time-varying information. As in traditional databases, joins are the most important and costly operators in temporal databases. Hence, efficient processing strategies for temporal joins are needed. The Entity Join operation is used to group temporal attributes of an entity into a single relation, and is important because those temporal attributes are likely to reside in separate relations due to normalization. In this paper, we propose an efficient Entity-join algorithm for both non-ordered and append-only temporal databases. The proposed approach can be applied to other temporal join operations, such as valid-time equijoin.

Specification of Calendars and Time Series for Temporal Databases

Abstract: Most temporal data models have concentrated on describing temporal data based on versioning of objects, tuples, or attributes. The concept of time series, which is often needed in temporal applications, does not fit well within these models. The goal of this paper is to propose a generalized temporal database model that integrates the modeling of both version-based and time-series based temporal data into a single conceptual framework. The concept of calendar is also integrated into our proposed model. We also discuss how a conceptual Extended-ER design in our model can be mapped to an object-oriented or relational database implementation.