Processing User Queries

SMQS.COM

DBC.COM

Wrapper 1

Wrapper 2

Mediator

Select Q.last, Q’.volume

from Quotes1 Q, Quotes2 Q´

where Q.ticker = Q´.ticker and

Q.company = “Oracle”

Select last, ticker

from Quotes1

where company = “Oracle”

Select volume, ticker

from Quotes2

where company = “Oracle”