DATABASES Exploiting Relational Database Technology in GIS

All systemsfor managing dataface commonproblems such as backup, recovery,auditing, security, data integrity and concurrent update. Other challenges include the ability to share data easily betweenapplications and to distribute data across several computers, while continuing to manage the problems already mentioned. Geographic information systems are no exception, and need to tackle all these issues. Standard relational databasemanagementsystemsprovide manyfeatures to help solve the issues mentionedso far. This article describeshow the IBM geoManager product approaches these issues by storing all its geographic data in a standard relational database product in order to take advantage of such features. Areas in which standard relational database functions need to be extendedare highlighted, and the way in which geoManager doesthis is explained.Theperformance implications of storing all data in the relational databaseare discussed. An important distinction is made between the storage and managementof geographic data and the manipulation and analysis of geographic data, which needs to be made when considering the applicability of relational database technology to GIS