collaborative query processing based on reducts
DESCRIPTION
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" - PowerPoint PPT PresentationTRANSCRIPT
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 Flightswhere airline = "Delta”departure time = "morning"departure airport = "Charlotte"aircraft = "Boeing"
(a1*c2)+(d2*a2)
(a1*c2)+(a1*b2*a2+d2*a2)
(a1*c2)+(a1*b2+d2)*a2
(g1, a2)
(g1, a2, a1)
(f2, a1*b2+d2)
(f2, a1*b2+d2, a2*d1)
{d,c,e,g}{a,b,c,d,f}={c,d} {a,b}, {a,c}, {b,c} {d,c,e,g}
= q (c, e, f (b(e), c ))
= q (c, e, f (b, c )) =
q = q (c, e, f ) = q
S1
e
cb
fec S1
S1
S2
S2
S3
Tree-resolution for q