List names of employees born after 1957 who work on project aquarius'

1
List names of employees born after 1957 who work
on project aquarius.
Inefficient strategy Cartesian products, then
selects, then projects.
? Lname

• Pname aquarius AND
• Pnumber pno AND
• essn ssn AND
• bdate gt 12/31/57

X
Project
X
Employee
Works-on
2
List names of employees born after 1957 who work
on project aquarius.
Medium strategy joins, then selects, then
projects.
? lname

• pname aquarius AND
• bdate gt 12/31/57

pnumber pno
Project
essn ssn
Employee
Works-on
3
List names of employees born after 1957 who work
on project aquarius.
Efficient strategy selects first, then joins,
then projects.
? lname
essn ssn
? bdate gt 12/31/57
pnumber pno
Employee
Works-on
? pname aquarius
Project