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1what main conclusions can you draw from the discussion of the ve basic le organizations discussed in section 84 which
explain the difference between hash indexes and b-tree indexes in particular discuss how equality and range searches
1consider the instance of the students relation shown in figure sorted by age for the purposes of this question assume
1answer the following questions about data on external storage in a dbmsnbsp1 why does a dbms store data on external
briefly answer the following questionsnbsp1 if the system fails repeatedly during recovery what is the maximum number
the description in section 1861 of the analysis phase made the sim-plifying assumption that no log records appeared
1consider a relation r with ve attributes abcde you are given the following dependencies a rarr b bc rarr e and ed rarr
briefy answer the following questions1 define the term functional dependency2 why are some functional dependencies
1consider the following collection of relations and dependencies as-sume that each relation is obtained through
suppose you are given a relation r with four attributes abcd for each of the following sets of fds assuming those are
consider a relation r that has three attributes abc it is decom-posed into relations r1 with attributes ab and r2 with
1jds are motivated by the fact that sometimes a relation that cannot be decomposed into two smaller relations in a
let r be decomposed into r1 r2 rn let f be a set of fds on rnbsp1 dene what it means for f to be preserved in the set
consider a relation r with ve attributes abcde1 for each of the following instances of r state whether it violates a
1describe a linear-time in the size of the set of fds where the size of each fd is the number of attributes involved
1give an algorithm for testing whether a relation scheme is in bcnf the algorithm should be polynomial in the size of
1prove that an mvd x rarrrarr y over a relation r can be expressed as the join dependency xy xr minus y 2let r be a
prove that the algorithm for decomposing a relation schema with a set of fds into a collection of bcnf relation schemas
consider the following bcnf schema for a portion of a simple cor-porate database type information is not relevant to
1the globetrotters club is organized into chapters the president of a chapter can never serve as the president of any
consider the following bcnf relational schema for a portion of a company database type information is not relevant to
consider the following bcnf relation which lists the ids types eg nuts or bolts and costs of various parts along with
1for each of the following queries identify one possible reason why an optimizer might not nd a good plan rewrite the
consider the following bcnf relations which describe departments in a company and employeesdeptdid dname location