  The basic aim of our study is to give a possible model for handling uncertain
information. This model is worked out in the framework of DATALOG. At first the
concept of fuzzy Datalog will be summarized, then its extensions for
intuitionistic- and interval-valued fuzzy logic is given and the concept of
bipolar fuzzy Datalog is introduced. Based on these ideas the concept of
multivalued knowledge-base will be defined as a quadruple of any background
knowledge; a deduction mechanism; a connecting algorithm, and a function set of
the program, which help us to determine the uncertainty levels of the results.
At last a possible evaluation strategy is given.
