A database is a large, computerized collection of structured data. In the non-spatial domain, databases have been in use since the 1960s for various purposes, such as bank account administration, stock monitoring, salary administration, sales and purchasing administration and flight reservation systems. These applications have in common that the amount of data is quite large, but the data themselves have a simple and regular structure. Designing a database is not an easy task. First, one has to consider carefully what the purpose of the database is and who its users will be. Second, one needs to identify the available data sources and define the format in which the data will be organized within the database. This format is usually called the database structure. Only when all this is in place can data be entered into the database. Data must be kept up to date and it is, therefore, wise to set up the processes for doing this and to make someone responsible for regular maintenance. Documentation of the database design and set up is crucial for an extended database life (proprietary databases tend to outlive the professional careers of their original designers).