SQL and Database Design Quiz

Which SQL keyword is used to enforce a condition that a column cannot contain NULL values?

• NOT NULL

• PRIMARY KEY

• UNIQUE

• CHECK

What is a partial dependency in database design?

• When a non-key attribute depends on only part of a composite key

• When a foreign key links two tables

• When a column can store multiple values

• When a primary key is not unique

In SQL, which of the following is a character data type?

• BOOLEAN

• CHAR

• INT

• DATE

In SQL, how do you ensure that a column must always have a value?

• By adding the FOREIGN KEY constraint

• By adding the NOT NULL constraint

• By adding the CHECK constraint

• By adding the UNIQUE constraint

What is the purpose of the SELECT statement in SQL?

• To modify existing records

• To create a new table

• To delete data

• To retrieve data from a database

Which of the following is a "bad" design for a database table?

• A table without NULL values

• A table with redundant data

• A table with atomic values

• A table with a foreign key

In SQL, which of the following commands is used to remove a table from the database?

• REMOVE TABLE

• DELETE TABLE

• ALTER TABLE

• DROP TABLE

What does the UNIQUE constraint ensure in a database table?

• All values in a column must be unique

• A column can store multiple values

• All values in a column must be NULL

• A column can have repeated values

What is a Primary Key (PK)?

• A field that connects two tables

• A field that stores multiple values

• A field that contains NULL values

• A field that uniquely identifies a row in a table

What type of constraint would be used to ensure that students' birthdates are after 1980?

• UNIQUE

• PRIMARY KEY

• NOT NULL

• CHECK