Is it possible to have two clustering indexes on the same table? a) yes, b) no,

Question

Is it possible to have two clustering indexes on the same table? a) yes, b) no, c) it depends on the table. __________.

Consider the following query:

select * from contributor
where occupation="TEACHER"
order by name;

Would creating an index on attribute 'name' be likely to speed up this query? (yes/no) ___________

Suppose we are looking up a record in a database using a linear scan on the table. There are 100,000 records in the table, each block can hold exactly 100 records, the disk access time is 10 milliseconds, and the disk transfer time is 0.1 milliseconds per block. We are looking up the record using the table's primary key. What is the estimated cost of the lookup? (Remember that the cost is given in units of time.) ______________________

Suppose S and S' are serial schedules for transactions T1 and T2. Does this mean that S can be transformed to S' by a series of swaps of non-conflicting operations? (yes/no) ________

Explanation / Answer

1

c

It depends upon the table

Because it should have some relationship between two tables

2

Yes it can speed up the query

There should be no duplicates

It plays important role in query optimization

3

There are approximately 1024 blocks of data

estimates cost will be 2.5

4

Yes

It will swaps the series

joins will be used in this case

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