Crowdly

StudentID → AdvisorEmail

StudentID → StudentName

AdvisorName → AdvisorEmail

Which of the following scenarios illustrates a violation of Logical Data Independence in the ANSI-SPARC architecture?

Changing the underlying file format from CSV to PostgreSQL without modifying the conceptual schema.

Creating new views for different user groups without modifying the conceptual schema.

Modifying the conceptual schema by adding a new attribute to an entity and requiring all external schemas to be updated to include the new attribute

Updating the indexing structure of a relational database to improve query performance without altering the conceptual or external schemas

The ANSI/SPARC architecture defines three levels of database architecture: External, Conceptual, and Internal. A company wants to change the underlying storage format from CSV files to a PostgreSQL database for performance improvement. This change should be made at which level?

Conceptual Level

Internal Level

External Level

Data Independence Level

In a car rental system, the Rental table includes car_id, customer_id, and rental_date. Which keys should be part of the composite primary key?

Only car_id

car_id and customer_id

Only customer_id

car_id, customer_id, and rental_date

What type of key is used to uniquely identify each row in a table, but is not derived from the data itself?

Composite key

Surrogate key

Foreign key

Candidate key

In a library system, the relationship between Book and Author is M:N. Which of the following is true for the relational schema?

Store author names in a multivalued attribute in Book

Book table must contain author IDs

Create a BookAuthor table with FKs to both

Author table must contain book IDs

In a movie database, each director may direct multiple movies. What is the correct foreign key placement when mapping this 1:M relationship?

Create a new junction table

Place movie_id in the Director table

Place director_id in the Movie table

Place director_id in the Director table

You are designing an ERD for a bike sharing service. Bikes are uniquely identified and can appear at different stations over time. The bike’s current station

A foreign key referencing the Station table

A multivalued attribute of Bike

A composite entity

A derived attribute

In a video streaming platform, the WatchHistory includes the user ID, video ID, watch timestamp, and duration. WatchHistory is best modeled as:

A weak entity with no attributes

A multivalued attribute

A recursive relationship

A composite entity with a composite primary key

Which of the following is NOT a valid requirement for a table to be a relation?

Unique column names