About Ill-Known Data and Equi-Join Operations
In this paper, we are concerned with the querying of databases that may contain ill-known attribute values represented by possibility distributions. While the operations of selection and projection can be straightforwardly extended in such a context, this is not the case for the equi-join operator for which several semantics are possible. These different semantics are pointed out, as well as the corresponding situations in terms of information need. The issue of query compositionality is also examined in each case.
KeywordsPossibility Distribution Possibility Theory Linguistic Label Possibility Degree Selection Query
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