Week 1 practive quiz

Question 1

Which of the following is a correctly formatted database query?

1) What will be the temperature in New York City tomorrow?
2) Is there a correlation between oil prices and temperature?
3) What is the name of the student with ID number 2357?
4) What is the best U.S. state for retirement?

Answer 1

3) What is the name of the student with ID number 2357?

his is a correctly formatted database query.

Question 2

What is the role of a relationship in a database?

1) It connects two attributes.
2) It connects two entities.
3) It is part of a relation.
4) It helps users connect to a remote database.

Answer 2

2) It connects two entities.

Two entities are connected by one relationship.

Question 3

• Which of the following can be an entity name in a database?

1) Age
2) First Name
3) Gender
4) Student

Answer 3

4( Student

First Name cannot be an entity name because it is a characteristics with single value.

Entity = table

Question 4

What is required in order to use the cartesian product operator on two relations?

1) There must be at least one common attribute in the two relations.
2) The number of attributes in each relation must be the same.
3) The number of tuples in each relation must be the same.
4) It can be applied to any two relations without a requirement.

Answer 4

4) It can be applied to any two relations without a requirement.

The cartesian product does not require any condition.

Question 5

• Consider two relations A and B in a database. Relation A has 5 rows and relation B has 3 rows. How many rows are produced if we apply the cartesian product operation to A and B?

1) 15
2) 8
3) 3
4) 5

Answer 5

1) 15

The number of rows created by the cartesian product is found by multiplying the number of rows in each relation.

Question 6

Which mathematical operator must be used in order to display information about students who are majoring in Computer Science but not in Electrical Engineering?

1) Cartesian Product
2) Union
3) Intersection
4) Difference

Answer 6

4) Difference

The difference operator displays the requested information.

Question 7

• Which statement about the selection operator is true?

1) It requires more than one database as its input.
2) It filters certain attributes in a relation based on given criteria.
3) It filters certain tuples in a relation based on given criteria.
4) It requires more than one relation as its input.

Answer 7

3) It filters certain tuples in a relation based on given criteria.

The selection operator specifies tuples in a relation, not its attributes.

Question 8

• Which mathematical operator must be used in order to display information about students who are majoring in both Computer Science and Electrical Engineering?

1) Intersection
2) Cartesian Product
3) Difference
4) Union

Answer 8

1) Intersection

The union operator will display information about students who are majoring in either Computer Science or Electrical Engineering or both.

Question 9

Which mathematical operation must be completed before the ϴ-Join operation?

1) Multiplication
2) Intersection
3) Cartesian product
4) Union

Answer 9

3) Cartesian product

The ϴ-Join operation requires cartesian product.

Question 10

For which of the following functions require database management software because typical spreadsheet software cannot implement it?

1) Search data
2) Create multiple user types
3) Update data
4) Store data

Answer 10

2) Create multiple user typDatabase management software can create multiple user types, but spreadsheet software cannot.

Question 11

What connects two entities in a database?

1) Record
2) Relation
3) Table
4) Relationship

Answer 11

4) Relationship

Two entities are connected by a relationship.

Question 12

What is the name of the operation used for joining two relations?

1) ⋈-Join
2) ϴ-Join
3) β-Join
4) α-Join

Answer 12

2) ϴ-Join

This is the name of the operation used for joining two relations.

Question 13

• Which operator must be used to display information about students majoring in Mathematics or Physics

1) Union
2) Difference
3) Cartesian Product
4) Intersection

Answer 13

1) Union

The union operator displays information about students majoring in either Mathematics, Physics, or both.

The intersection operator displays information about students who are majoring in both areas.

Question 14

Which of the following two operators must be used one after another?

1) Cartesian Product, ϴ-Join
2) B: Union, ϴ-Join
3) Multiplication, ϴ-Join
4) Cartesian Product, Multiplication

Answer 14

these two operators can be implemented independently.

NOT 2) B: Union, ϴ-Join

Question 15

What must be listed after the SELECT command in a SQL query?

1) Attributes
2) Tables
3) Records
4) Conditions

Answer 15

1) Attributes

The SELECT command requires one or more attributes to be listed.

Question 16

• What must be listed after the FROM command in a SQL query?

1) Tables
2) Attributes
3) Records
4) Conditions

Answer 16

1) Tables

the FROM command does not need attributes to be listed

Question 17

What must be listed after the WHERE command in a SQL query?

1) Conditions
2) Tables
3) Attributes
4) Records

Answer 17

1) Conditions

The WHERE command requires one or more conditions to be listed.

Question 18

What is the function of the DISTINCT command in a SQL query?

1) To eliminate duplicate columns
2) To eliminate duplicate rows
3) To eliminate duplicate relations
4) To eliminate duplicate relationships

Answer 18

2) To eliminate duplicate rows

The DISTINCT command eliminates duplicate rows from query results.

Question 19

A particular query that pulls information from one or more tables is an example of a:

1) View
2) Conceptual Schema
3) Relation
4) Physical Schema

Answer 19

1) View

A view can combine data from two or more table, using joins, and also just contain a subset of information.

Question 20

Which of the following database types is most oriented toward storing well-structured data?

1) Relational Database
2) Hadoop
3) NoSQL Database
3) Spark

Answer 20

1) Relational Database

A relational database is based on the relational model of data, and is therefore well-structured.

Question 21

• A participation constraint is indicated how in an ER diagram.

1) A line
2) A dotted line
3) A bold line
4) A dashed line

Answer 21

3) A bold line

A participation constraint defines the relationship of an attribute in a connected relation and is not represented by a dashed line.

Question 22

What does the relational algebra operator ‘x’ indicate?

1) All pairs from the two tables matched on a specified field.
2) The intersection of the two tables.
3) All possible pairs from the two tables.
4) The union of the two tables.

Answer 22

3) All possible pairs from the two tables.

Cartesian product of a set of n-tuples with a set of m-tuples yields a set of “flattened” (n * m) tuples

Question 23

The basic syntax for an SQL query is:

1) TARGET, RELATION, DISTINCT
2) SELECT, FROM, WHERE
3) DISTINCT FROM QUALIFICATION
4) DISTINCT, FIELD, ID

Answer 23

2) SELECT, FROM, WHERE

The basic syntax of a SQL query is SELECT, FROM, WHERE