Showing papers by "Ramez Elmasri published in 2001"

Fundamentals of Database Systems with Cdrom and Book

Abstract: From the Publisher: Each copy of this best-seller is now accompanied by a CD-ROM containing an electronic version of the book, allowing readers to highlight text, make margin notes and more. Fundamentals of Database Systems combines clear explanations of theory and design, broad coverage of models and real systems, and excellent examples with up-to-date introductions to modern database technologies. It focuses on the relational model and includes recent object-oriented developments such as SQL3 and ODMG. The authors provide coverage of the popular DBMS products, in particular the relational systems Oracle and Microsoft Access. They also address advanced modeling and system enhancements in the areas of active databases, temporal and spatial databases, and multimedia data models. The book also surveys the latest application areas of data warehousing, data mining, digital libraries, GIS, and genome databases. This book is appropriate for programmers looking for an introduction to database theory and application, or a reference to how popular real-world DBMSs address these concepts.

Schema versioning and database conversion techniques for bi-temporal databases

Abstract: Schema evolution and schema versioning are two techniques used for managing database evolution Schema evolution keeps only the current version of a schema and database after applying schema changes Schema versioning creates new schema versions and converts the corresponding data while preserving the old schema versions and data To provide the most generality, bi-temporal databases can be used to realize schema versioning, since they allow both retroactive and proactive updates to the schema and database In this paper we first study two proposed database conversion approaches for supporting schema evolution and schema versioning: single table version approach and multiple table version approach We then propose the partial table version approach to solve the problems encountered in these approaches when applied to bi-temporal databases

Utilizing object-oriented databases for concurrency control in virtual environments

Abstract: Virtual Reality Modeling Language (VRML) is widely used to represent, create, and display virtual reality objects and their environment. Some VRML applications require concurrent interaction by multiple users in a real-time distributed fashion. Such applications need a method for users to share and update the VRML objects in real-time. To allow concurrent shared real-time access, our approach is to store the VRML objects in an object-oriented database system (ObjectStore) in order to utilize the concurrency control mechanisms of the system. The authors present an architecture that allows multiple users to interact in a non-trivial way in such a shared VRML environment. We outline how the VRML world can be saved in ObjectStore and implement a series of test cases demonstrating concurrency issues arising from simultaneous updates. Our architecture uses ordinary Java enabled Web browsers with a VRML plug-in. A commercial Web server routes client requests to a custom application server which interacts with the object-oriented database. As users change the VRML world, our application server orders the requests and updates the master copy in the database.

A temporal algebra for an ER-based temporal data model

Abstract: There have been many temporal data models proposed in the literature. Most of them are based on relational models. Despite their popularity as design and analysis tools for information systems, entity-relationship (ER) based temporal data models have not drawn as much attention as those based on relational models. One reason is that most ER-based temporal data models lack an underlying formalism and algebra. If a conceptual model, along with an algebra, is formally defined, we can design a query language that operates on the conceptual model rather than on the implementation model. Also, it can provide a basis for a user-friendly visual query language. In this paper, we present a temporal algebra for an ER-based temporal data model called ITDM (Integrated Temporal Data Model). We define ten algebraic operations and ten temporal aggregate operations. We also define time-series-specific operations.

Extracting XML DTDs from Relational Schemas in the WebOntEx System.

Abstract: Publisher UPGRADE is published on behalf of CEPIS (Council of European Professional Informatics Societies, ) by Novática , journal of the CEPIS society ATI (Asociación de Técnicos de Informática, Spain ) UPGRADE is also published in Spanish (full issue printed, some articles online) by Novática, and in Italian (online edition, abstracts only) by the Italian CEPIS society ALSI and the Italian IT portal Tecnoteca UPGRADE was created in October 2002 by CEPIS and was first published by Novática and by Informatik/Informatique, bimonthly journal of SVI/FSI (Swiss Federation of Professional Informatics Societies, )

Integration of Object-Oriented Databases with VRML in Virtual Environments

Abstract: Virtual Reality Modeling Language (VRML) is widely used to represent, create, and display virtual reality objects and their environment. Some VRML applications require concurrent interaction by multiple users in a real-time distributed fashion. Such applications need a method for users to share and update the VRML objects in real-time. To allow concurrent shared real-time access, our approach is to store the VRML objects in an object-oriented database system (ObjectStore). In this paper, we present an architecture that allows multiple users to interact in a non-trivial way in such a shared VRML environment. We outline how the VRML world can be saved in ObjectStore.

ADTP: a new protocol for data processing over the internet

Abstract: Emerging e-commerce applications typically use a Web server and CGI (Common Gateway Interface)for data processing. This client/server architecture is suitable when the Internet is not congested and the database server is not overloaded, but it may cause problems if congestion and overloading occur. A certain class of DPS (Data Processing System) applications, such as order processing or sales reporting, do not require real-time response, so they may utilize email (Simple Mail Transport Protocol) or other protocols that allow delaying or relaying of data. In this paper, we propose an innovative model of DPS (the Senddata System) that avoids congestion on the Internet and exploits a database server around the clock. Our model provides easy access to the database server and fits naturally in the middle tier of the three-tier model for database access, while providing performance and security. E-commerce applications may use our model in the presence of congestion on the Internet or unavailability of the server.

A CASE Tool for Object-Oriented Database Design

Abstract: There have been many CASE tools developed for designing Relational Database applications. However, not many CASE tools exist for designing Object-Oriented Database (00DB) applications. A key difference is that OODBs have methods or operations in addition to the data structures; hence, an Automatic Code Generation module is needed for such a CASE tool. This paper describes algorithms that embed the integrity constraints into the methods so that automatic constraint checking is done when any of the basic methods are invoked. The basic methods we consider are the constructor (for creating new objects of a class), destructor (for removing objects), modifier (for modifying attribute or instance variables), relator (for relating objects), and unrelator (for removing object relationships). The CASE tool has a Graphical User Interface (GUI) which takes an Enhanced Entity-Relationship (EER) schema as an input and creates a textual representation of EER schema objects. This is then transformed and stored in the CASE tool directory and an Automatic Code Generation program generates code skeletons for generic methods (operations) for the object classes. Automatic Code Generation program generates the code for the ODE object-oriented DBMS classes after mapping from the EER to an OO schema.