Database Concepts Quiz

In an ER diagram, what does a diamond shape represent?

• Entity

• Attribute

• Relationship

• Key

What is the primary goal of database normalization?

• To speed up query execution

• To reduce data redundancy and improve data integrity

• To create more tables in the database

• To simplify SQL queries

Which normal form is achieved when a table is in 2NF and no non-prime attribute is transitively dependent on the primary key?

• First Normal Form (1NF)

• Second Normal Form (2NF)

• Third Normal Form (3NF)

• None of the above

Consider a table with attributes A,B,C,D,E and the following functional dependencies: A→B, B→C, C→D, and A→E. Which normal form is the table currently in?

• 1NF

• 2NF

• 3NF

• BCNF

In the context of relational databases, what is a composite key?

• A single attribute that uniquely identifies a record

• A combination of two or more attributes that uniquely identify a record

• An attribute that can accept null values.

• A foreign key that refers to a primary key in another table

Answer: B) A combination of two or more attributes that uniquely identify a record

Consider a table with the attributes A,B,C,DA, B, C, DA,B,C,D. The attribute AAA is a primary key, and there are no other candidate keys. Which of the following statements is true?

• AAA is the only candidate key, and it is also the primary key.

• B,C,B, C,B,C, and DDD are candidate keys.

• AAA cannot be the primary key because there are no other candidate keys.

• A,B,C,A, B, C,A,B,C, and DDD together form the primary key.

Which of the following statements about foreign keys is true?

• A foreign key must reference a primary key in the same table.

• A foreign key establishes a relationship between two tables.

• A foreign key can only reference a composite key.

• A foreign key is used to enforce unique constraints on the referenced column.

If a table is in 1NF and every non-key attribute is fully functionally dependent on the primary key, but some attributes are transitively dependent on the primary key, which normal form is the table in?

• 1NF

• 2NF

• 3NF

• BCNF

What is the purpose of a foreign key in a database?

• To establish a relationship between two tables.

• To enforce unique constraints on the referenced column.

• To speed up query execution.

• To simplify SQL queries.

What does a double-lined box represent in an ER diagram?

• Entity

• Attribute

• Relationship

• Key