Consider the following two relations: Sailors(sid: integer, sname: string, ratin

Question

Consider the following two relations: Sailors(sid: integer, sname: string, rating: integer, age: real), where attribute sid is the primary key of the relation, and Reserves(sid: integer,_bid integer,_day: _date), where all three attributes collectively are the primary key of the relation There is only one index in the database, namely, a hash index on attribute sid of the Sailors relation. Consider the natural join of Sailors and Reserves: SELECT FROM Sailors S, Reserves R WHERE S.sid-R.sid Explain how you can improve the "naive" nested loops algorithm that we covered in class so that you can take advantage of the hash index on Sailors.sid when computing the above natural join.

Explanation / Answer

Solution:

The algorithm can be improved in such a way that we perform the join only based on the primary key of Sailor which is Sid, and based on that number of iterations running in the code of nested loop join will decrease and we can have an optimized algorithm to get the join.

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