Write in relational algebra Determine how many different types of plows there ar

Question

Write in relational algebra

Determine how many different types of plows there are and then determine which drivers may drive this number. This requires counting...?

Tables
primary keys in bold

Foreign keys underlined

Driver (Driver License#, Driver Name, Driver Phone#)

Plow Type (Plow Type Name)

Plow (Plow VIN, Plow Type Name, At Garage ID)

Garage (Garage ID, Garage Address)

Muni(Municipality Name, Muni Contact Person, Contact Address, contact Phone#, Contract# Contract Description, Contract Dollar Amount)

Billing (Municipality Name, Start Date, Billed Date, Paid?, Paid Date)

Storm Event (Start Date, End Date)

May Drive (Driver License#, Plow Type Name)

Schedule (Municipality Name, Start Date, Driver License#, Plow VIN)

Explanation / Answer

Select count(distinct(plow type name) as plows from plow type; Select Driver Name from Driver d, may Drive m, where d.Driver Licence# = m.Driver Licence# and plows = Select count(distinct(plow type name) as plows from plow type;

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.