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Query Cost for MA.Hashing (cont)

For a relation  R(a,b,c,d)  ...

select * from R where a=1
-- has 1 specified attribute (a)
-- has 3 unspecified attributes (b,c,d)

select * from R where b=5 and d=2
-- has 2 specified attributes (b,d)
-- has 2 unspecified attributes (a,c)

select * from R
where a=1 and b=5 and c=3 and d=2
-- has 4 specified attributes (a,b,c,d)
-- has 0 unspecified attributes