DBMS - DATA STORAGE AND QUERYING MCQ

Database

Title
Which of the following operations are associative
Which of the following set operations is not commutative?
State true or false: The projection operation does not distribute over the union operation
If no rule can be derived from any combination of others then the set of rules is said to be ________
Theta join operations are
Which of the following operations is associative
Which of the following set operations does the selection operation distribute over?
State true or false: Multiple equivalence rules can be used one after the other on a query
Which of the following information does the database system catalog store?
Most databases store the distribution of values for each attribute as a __________
What is the function of the equi-width histogram?
What kind of a sample must be used for statistical analysis?
The ________ SQL command generates statistics on a particular relation
The union of all records satisfying the individual simple conditions Oi is called as ________
The intersection of all records satisfying the individual simple conditions Oi is called as ________
State true or false: Estimation of the size of the result of a join is not possible
Size estimation can be done for which of the following processes?
The size of a _____ is simply V(A,r) where r is the relation and A is a distinct value
A ________ explores the space of all query evaluation plans that are equivalent to a given query
What is the disadvantage of cost based optimizers?

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