SQL JOIN

Multiple Choice

What is a table relationship?

• A link between two tables based on shared values

• A method to store data in one table

• A way to visualize data

• A type of database query

Multiple Choice

What does the one-to-one relationship between Students and ID Cards imply?

• Each student can have multiple ID cards

• Each ID card can belong to multiple students

• Each student has exactly one ID card

• ID cards are not linked to students

Multiple Choice

Which type of relationship allows one row in A to relate to many rows in B?

• One-to-One

• One-to-Many

• Many-to-Many

• None of the above

Multiple Choice

What is the purpose of a junction table in a many-to-many relationship?

• To store primary keys only

• To hold foreign keys and extra info about relationships

• To create a one-to-one relationship

• To eliminate redundancy in data

Multiple Choice

What is the purpose of a FOREIGN KEY in a database?

• To create a new table

• To enforce a link between tables

• To delete data from a table

• To update records in a table

Multiple Choice

What does referential integrity mean in the context of databases?

• It allows any foreign key value in a child table.

• It requires every foreign key value in a child table to match an existing primary key value in the parent table or be NULL.

• It prevents the deletion of any section in the database.

• It allows for orphan rows in the database.

Multiple Choice

What does the CASCADE action do in a database management system?

• Automatically delete child rows

• Block the operation if related child rows exist

• Set foreign key in child rows to NULL

• No action taken

Multiple Select

What are the steps in the process of designing related tables for multi-table databases? Select all possible correct answer.

• List the Entities

• Define Attributes

• Pick a Primary Key

• Identify Relationships

• Add Foreign Keys

Multiple Choice

What is the purpose of a JOIN in SQL?

• To combine rows from two or more tables

• To delete rows from a table

• To create a new table

• To update existing rows

Multiple Choice

What does an INNER JOIN return in SQL?

• Only rows with matching values in both tables

• All rows from both tables

• Only unmatched rows from both tables

• Rows with NULL values

Multiple Choice

What does a LEFT JOIN return in SQL?

• Only matched rows from both tables

• All rows from the right table

• All rows from the left table, plus matched rows from the right

• Only rows with NULL values

Multiple Choice

What does a RIGHT JOIN return in SQL?

• Only matched rows from both tables

• All rows from the LEFT table

• All rows from the RIGHT table, plus matched rows from the LEFT

• Only rows with NULL values

Multiple Choice

In the provided SQL query, which table is joined to get the section name?

• students

• sections

• enrollments

• subjects

Multiple Choice

What SQL command is used to retrieve every student's name, the section they belong to, and the subjects they are enrolled in?

• SELECT

• JOIN

• INNER JOIN

• FROM