Abstract
It is sometimes necessary to operate on data having different sets of attributes. It can be caused by the fact that the data come from different sources or that we collected different amount of information about different realworld entities.
In such cases a unification of the data to be stored into tables causes either data loss or too frequent changes in the table/database layout. Therefore we propose a data model allowing effective handling of such data.
The model, originally developed for storage and processing of non-graphic data in a temporal GIS, ensures that all procedures/functions/methods are performed only on objects having all data necessary for their successful completion. Such features enable easier creation of context-aware and context-adaptable applications.