Suggest the indexes that can be added to this database in order to improve the performance of this query. Indicate whether these indices should be clustered or not. Explain your reasoning briefly.
Consider the following relational schema:
Student(Id,Name,Major)
Took(StudId,Course)
where Id is the primary key in Student. Consider the query
SELECT *
FROM Student S, Took T
WHERE S.Id = T.StudId AND T.Course = 'CS305' AND S.Major = 'EE'
Clustered index on Course in Took, since it will facilitate the rst selection. A clustered index on Major in Student might also help, since it can facilitate the second selection. Note that although Id is a primary key in Student, it might have an unclustered (rather than clustered) index, because numeric single-attribute keys often have unclustered hash indices.
We could do away with the clustered index on Major, since we could also do the join using the index on Id, which exists because Id is the primary key.
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Readability statistics measure the reading level of a document by checking all of the following EXCEPT:
A) length of words. B) length of paragraphs. C) length of sentences. D) number of pages.
In this chapter we have described sequence numbers between a sender and receiver as a way to protect a communication stream against substitution and replay attacks. Describe a situation in which an attacker can substitute or replay in spite of sequence numbers. For which type of sequence numbering—one general stream of sequence numbers or a separate stream for each pair of communicators—is
this attack effective? What will be an ideal response?
The CPU consists of three parts: the control unit, the ALU unit, and RAM.
a. true b. false