Integration of geodata < The relational database > Connecting geo-information with the database

3.3 — The relational database

A relational database consists of separate tables which are connected by different types of relations (Simovici & Tenney 1995, Harrington 1998). Storing related information within different tables avoids redundancy and spelling errors, and allows much more efficient data entry. The underlying structure of a database - the data model - is invisible to the user, who accesses the databases by pre-programmed graphical user interfaces. Experienced users can query the different tables by a Standard Query Language (SQL), which is similar for any relational database. This allows data exchange between different databases. Understanding the underlying data model allows extended possibilities for data analysis by SQL. This section describes the major modules of the database, as shown in the block diagram (Figure 3.3). Each module could be considered a relational database in its own right. The modular design allows easy extension with additional information layers in the future.

Fig. 3.3:

Block diagram of the GROMS data model. Each module can be considered as an independent database. All data are fully referenced. Therefore, the reference section is a central part of the database. Geo-objects such as lines and polygons have to be stored outside the database, but their file names are administered by the geo-object module.

Abb. 3.3:

Blockdiagramm des GROMS Datenmodells. Jedes Modul kann als eigenständige Datenbank betrachtet werden. Alle Dateneinträge enthalten die Quellenangabe. Daher ist das Literaturmodul ein zentraler Bestandteil der Datenbank. Die Geoobjekttypen "Linien" und "Polygone" werden außerhalb der Datenbank gespeichert, aber die Dateinamen werden von der Datenbank verwaltet.

In accordance with the different thematic areas, the database contains the following thematic modules:

Integration of geodata < The relational database > Connecting geo-information with the database

This document should be quoted as part of the publication "Riede, K. (2001): The Global Register of Migratory Species ­ Database, GIS Maps and Threat Analysis. Münster (Landwirtschaftsverlag), 400 pp." + CD

 by Klaus Riede