A Structure-Based Model of Semantic Integrity Constraints for Relational Databases

Database management systems (DBMSs) are in widespread use because of the ease and flexibility with which they enable users to access large volumes of data. The use of DBMSs has spread from its origin in business applications to scientific and engineering applications as well. As engineers rely more and more on the computer for data storage, our ability to manually keep track of relationships between data and to ensure data accuracy is severely limited. The inherent fluctuations in engineering design data as well as its large volume, increase the difficulty of doing so. Ensuring data accuracy through the use of integrity constraints which limit or constrain the values of the data is a central aspect of DBMS use. Enforcing constraints (to the extend possible) is a job for the DBMS. This alleviates some of the burden placed on the user and database administrator to maintain the integrity of the database. In addition, it enables integrity constraints to be conceptually centralized and made available for inspection and modification instead of being scattered among application programs. Despite their importance, however, capabilities for handling integrity constraints in commercial DBMSs are limited and they lack adequate integrity maintenance support. In addition, a comprehensive theoretical basis for such support-the role of a constraint classification, representation, invocation, and use methodology-has yet to be developed. This paper presents a formalism that classifies semantic integrity constraints based on the structure of the relational database model. Integrity constraints are characterized by the portion of the database structure they access, whether one or more relations, attributes, or tuples. Thus, the model is completely general, allowing the identification, definition, and arbitrary specification of any constraint on a relational database. It also provides a basis for the implementation of a database integrity subsystem. Examples of each type of constraint are illustrated using a small engineering database, and various implementation issues are discusse

Infrastructure management information system framework requirements for disasters

A three-tiered, enterprise, GIS architecture offers a robust, efficient, and secure platform to potentially revolutionize disaster management by enabling support of all of the phases of governmental activity that must occur before, during, and after a disaster. Presently, both publicly and privately initiated, computer-based systems designed for disaster management cannot meet the real-time data access and analysis needs at crucial stages, especially those occurring during an actual disaster. Impediments are reflective of the proprietary, standalone, and segregated nature of current systems. This paper proposes an integrated, infrastructure management information system as a reliable and effective alternative. Issues related to sharing data, customizing applications, supporting multiple data formats, querying visually, facilitating ubiquitous computing, and upgrading are all addressed. Achieving maximum flexibility and capacity in a disaster management system relies upon recent advances in the following areas: (1) standardized data specifications, (2) middleware services, and (3) web-enabled, distributed computing. Key resources in designing and implementing such an arrangement are prototyped in a system that was initially designed for addressing disaster management of urban explosions. The critical details of that system are presented herein.Not applicableNeed to link to publisher version at: http://cedb.asce.org/cgi/WWWdisplay.cgi?156651. DG 05/07/2010. Changed forms of authors names (please check) - au ti ke ab 100729 RB

Infrastructure management information system framework requirements for disasters

A three-tiered, enterprise, GIS architecture offers a robust, efficient, and secure platform to potentially revolutionize disaster management by enabling support of all of the phases of governmental activity that must occur before, during, and after a disaster. Presently, both publicly and privately initiated, computer-based systems designed for disaster management cannot meet the real-time data access and analysis needs at crucial stages, especially those occurring during an actual disaster. Impediments are reflective of the proprietary, standalone, and segregated nature of current systems. This paper proposes an integrated, infrastructure management information system as a reliable and effective alternative. Issues related to sharing data, customizing applications, supporting multiple data formats, querying visually, facilitating ubiquitous computing, and upgrading are all addressed. Achieving maximum flexibility and capacity in a disaster management system relies upon recent advances in the following areas: (1) standardized data specifications, (2) middleware services, and (3) web-enabled, distributed computing. Key resources in designing and implementing such an arrangement are prototyped in a system that was initially designed for addressing disaster management of urban explosions. The critical details of that system are presented herein.Not applicableNeed to link to publisher version at: http://cedb.asce.org/cgi/WWWdisplay.cgi?156651. DG 05/07/2010. Changed forms of authors names (please check) - au ti ke ab 100729 RB