Database Management and Warehousing - Data Science & Artificial Intelligence Previous Year Questions

Consider a database that includes the following relations:
Defender(name, rating, side, goals)
Forward(name, rating, assists, goals)
Team(name, club, price)
Which ONE of the following relational algebra expressions checks that every name occurring in Team appears in either Defender or Forward, where \(\phi\) denotes the empty set?

If a relational decomposition is not dependency-preserving, which one of the following relational operators will be executed more frequently in order to maintain the dependencies?

Let R(A, B, C, D, E) be a relational schema with functional dependency set F={A→BC, CD→E, E→A}.

Which of the following statements is correct?

Consider the following two tables named Raider and Team in a relational database maintained by a Kabaddi league. The attribute ID in table Team references the primary key of the Raider table, ID.

Raider
ID	Name	Raids	RaidPoints
1	Arjun	200	250
2	Ankush	190	219
3	Sunil	150	200
4	Reza	150	190
5	Prathem	175	220
6	Gopal	193	215

Team
City	ID	BidPoints
Jaipur	2	200
Patna	3	195
Hyderabad	5	175
Jaipur	1	250
Patna	4	200
Jaipur	6	200

The SQL query described below is executed on this database:
SELECT *
FROM Raider, Team
WHERE Raider.ID=Team.ID AND City=”Jaipur” AND RaidPoints > 200;
The number of rows returned by this query is ______.

Consider the following three relations:
Car (model, year, serial, color)
Make (maker, model)
Own (owner, serial)
A tuple in Car represents a specific car of a given model, made in a given year, with a serial number and a color. A tuple in Make specifies that a maker company makes cars of a certain model. A tuple in Own specifies that an owner owns the car with a given serial number. Keys are underlined; (owner, serial) together form key for Own. (⋈ denotes natural join)
\(\pi_{owner}(\text{Own} \bowtie (\sigma_{color='red'}(\text{Car}) \bowtie (\sigma_{maker='ABC'}(\text{Make}))))\)
Which one of the following options describes what the above expression computes?

Consider that the visualization of a 3-dimensional data cube is showing Sales Quantity for each combination of the attributes Product Type, Month and Country.

From this, if we want to further visualize the Sales Quantity for each combination of Product Type, Month and State, which of the following OLAP operations should be performed?