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With relationship type CLAS, you should always specify the name of theclassifying field from the check table and its possible (classifying)value. The division of the entity into subentities is not clear unlessboth attributes are specified (relationship type CLAS). Example: Classification of documents into purchasing and sales document classes,where one document cannot belong to both classes at the same time. Aclassifying field is the document type which clearly indicates theclass to which a document belongs. Possible values for the classifyingfield (document type) are 'E' (purchasing document) and 'V' (salesdocument). |