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Collaborative query processing based on reducts. Example of a non-local query (DS-term). Database: Flights(airline; departure time; arrival time; departure airport; arrival airport). select * from Flights where airline = "Delta” departure time = "morning"
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Example of a non-local query (DS-term) Database: Flights(airline; departure time; arrival time; departure airport; arrival airport) select * from Flights where airline = "Delta” departure time = "morning" departure airport = "Charlotte" aircraft = "Boeing"
(f2, a1*b2+d2) (f2, a1*b2+d2,a2*d1) (g1,a2) (g1,a2,a1) (a1*c2)+(a1*b2+d2)*a2 (a1*c2)+(a1*b2*a2+d2*a2) (a1*c2)+(d2*a2)
{d,c,e,g}{a,b,c,d,f}={c,d} {a,b}, {a,c}, {b,c} {d,c,e,g}
q e S1 S1 S1 c f S2 S2 b c e S3 Tree-resolution for q q = q (c, e, f ) = = q (c, e, f (b, c )) = = q (c, e, f (b(e), c ))