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                              DATABASE SEMINAR
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                      Floris Geerts, University of Edinburgh
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                    Data completeness and the currency of data
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                   Wednesday, September 21, 2011 -- h 15:00
                           **** Sala riunioni ****
                    Dipartimento di Informatica e Automazione
                            Universita' Roma Tre
                             Via Vasca Navale, 79
                                 primo piano 
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                                    ABSTRACT
Data in real-life databases become obsolete rapidly. One often finds
that multiple values of the same entity reside in a database. While
all of these values were once correct, most of them may have become
stale and inaccurate. Moreover, these values often do not carry
reliable timestamps.
With this comes the need for studying data currency,  to identify the
current value of an entity in a database and to answer queries with
the current values, in the absence of timestamps. I'll present a
possible approach to model data currency.
Furthermore, one may wonder whether it is possible to complete the
database by copying more information such that the query result
becomes more recent and complete. That is, copying more information
into the database does not affect the query result. In this talk, I
overview some recent results on completing databases, both in the
currency and standard relational setting.
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