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sherlockxhouse

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  1. thank you very much mikosiko,, now i understand how they got the answers and i'm ready on my own.
  2. Hello there everyone, I have finally an answer on letter C and D questions. Letter C was confirmed correct by my instructor. Seems all of my classmates have same answers on Letter D yet no one can prove where did they get the "D2", they only say that they got the answer from internet I'm getting curios also where D2 came from. I would be grateful if somebody here does. Please. Thank you and more power. c. π driver_name ([π driver_id, bus_id (reserves) / π bus_id(σ bus_name=‘Shuttle’ (bus))] driver ) d. π D2.driver_id (σ D2.rating > driver.rating [ ρ (D2,Driver) × σ driver_name=‘Paul’ (Driver)] )
  3. Thank you!! in the event, i could try answering some of those questions, will you help me correct my work?
  4. I am just new to relational algebra probably a pre-step before learning SQL queries. Can you help me make the expressions of relational algebra expression for each of the following queries. This is the table contained inside a bus driver database. driver ( driver_id, driver_name, age, rating ); bus ( bus_id, bus_name, color); reserves ( driver_id, bus_id, date); a. Find the names of drivers who have reserved at least three busses. b. Find the names of drivers who have reserved all busses. c. Find the names of drivers who have reserved all busses called Shuttle. d. Find the IDs of drivers whose rating is better than some driver called Paul. I would be grateful if somebody can help me here.
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