Discuss 3 different ways variables can be used while creating data base management system

Suppose there is a relation r(a, b, c) with a b+-tree index with search keys (a, b).1. what is the worst-case cost of finding records satisfying 10 < a < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree? 2. what is the worst-case cost of finding records satisfying 10 < a < 50 and 5 < b < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above? 3. under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from part (2)?

Janice recently received her college degree and is looking for a job. she is worried that since she just finished school, she will be required to repay her perkins and direct subsidized loans immediately. janice pulls out the paperwork she signed and reviews it again for repayment information. after reading all of the information, janice discovers that

2. fluorine and chlorine molecules are blamed fora trapping the sun's energyob forming acid rainoc producing smogod destroying ozone molecules