Exercise 12.4 Consider the following schema with the Sailors relation: Sailors(sid: integer, sname: string, rating: integer, age: real) For each of the following indexes, list whether the index matches the given selection conditions. If there is a match, list the primary conjuncts. A B+-tree index on the search key < Sailors.sid >. σSailors.sid<50,000(Sailors) σSailors.sid=50,000(Sailors) A hash index on the search key < Sailors.sid >. σSailors.sid<50,000(Sailors) σSailors.sid=50,000(Sailors) A B+-tree index on the search key < Sailors.sid, Sailors.age >. σSailors.sid<50,000∧Sailors.age=21(Sailors) σSailors.sid=50,000∧Sailors.age>21(Sailors) σSailors.sid=50,000(Sailors) σSailors.age=21(Sailors) A hash index on the search key < Sailors.sid, Sailors.age >. σSailors.sid=50,000∧Sailors.age=21(Sailors) σSailors.sid=50,000∧Sailors.age>21(Sailors) σSailors.sid=50,000(Sailors) σSailors.age=21(Sailors) (note that the book has a typo for part 4, answer for hash index only)
Exercise 12.4 Consider the following schema with the Sailors relation:
Sailors(sid: integer, sname: string, rating: integer, age: real)
For each of the following indexes, list whether the index matches the given selection conditions. If there is a match, list the primary conjuncts.
A B+-tree index on the search key < Sailors.sid >.
σSailors.sid<50,000(Sailors)
σSailors.sid=50,000(Sailors)
A hash index on the search key < Sailors.sid >.
σSailors.sid<50,000(Sailors)
σSailors.sid=50,000(Sailors)
A B+-tree index on the search key < Sailors.sid, Sailors.age >.
σSailors.sid<50,000∧Sailors.age=21(Sailors)
σSailors.sid=50,000∧Sailors.age>21(Sailors)
σSailors.sid=50,000(Sailors)
σSailors.age=21(Sailors)
A hash index on the search key < Sailors.sid, Sailors.age >.
σSailors.sid=50,000∧Sailors.age=21(Sailors)
σSailors.sid=50,000∧Sailors.age>21(Sailors)
σSailors.sid=50,000(Sailors)
σSailors.age=21(Sailors)
(note that the book has a typo for part 4, answer for hash index only)
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