Generation of Symbolic Objects from Relational Databases

In former chapters, we have defined the concept of a ‘symbolic object’ in a formal way (with various levels of generality) and illustrated these definitions and the related terminology by many examples. Thereby we have emphasized the two-level-paradigm where symbolic objects were created quite naturally when aggregating single individuals (described by classical single-valued variables) into classes, and describing the more or less complex properties of these classes. Here, we focus on the generalization process from a classical dataset extracted from a relational database. We also define a specialization step which aims at reducing over-generalization. Finally, we present how to build a symbolic dataset from several datasets by applying a join operator.