AUS : Unit 4 - Normalization

What are the main types of normalization in DBMS?

• 1NF, 2NF, 3NF, BCNF, 4NF, 5NF

• 1NF, 2NF, 3NF, 4NF, 5NF, 6NF

• 1NF, 2NF, 3NF, 6NF

• 1NF, 2NF, 3NF, 4NF, 5NF, 7NF

Define First Normal Form (1NF).

• A table is in First Normal Form (1NF) if it contains only atomic values, each column has unique names, and all entries in a column are of the same data type.

• A table is in First Normal Form (1NF) if it allows duplicate values in a column.

• A table is in First Normal Form (1NF) if it contains nested tables within its columns.

• A table is in First Normal Form (1NF) if it has no restrictions on data types in each column.

What is the purpose of Second Normal Form (2NF)?

• To ensure all attributes are independent of the primary key.

• To eliminate all dependencies between attributes.

• To group related data into separate tables.

• To eliminate partial dependencies and ensure all non-key attributes depend on the entire primary key.

Explain the concept of Third Normal Form (3NF).

• A table is in Third Normal Form (3NF) if it is in Second Normal Form and all non-key attributes are functionally dependent only on the primary key.

• A table is in Third Normal Form if it has at least three columns.

• A table is in Third Normal Form if it has no primary key.

• A table is in Third Normal Form if it contains only numeric data types.

What distinguishes Boyce-Codd Normal Form (BCNF) from 3NF?

• BCNF allows transitive dependencies on candidate keys.

• BCNF does not allow any functional dependencies.

• 3NF requires every determinant to be a superkey.

• BCNF requires every determinant to be a candidate key, while 3NF allows transitive dependencies on superkeys.

What is a functional dependency in the context of databases?

• A functional dependency is a way to encrypt data in a database.

• A functional dependency is a method for indexing data in a database.

• A functional dependency is a type of database normalization technique.

• A functional dependency is a relationship where one attribute uniquely determines another attribute in a database.

How does normalization help in reducing data redundancy?

• Normalization increases data duplication by merging tables.

• Normalization helps reduce data redundancy by organizing data into related tables, ensuring each piece of information is stored only once.

• Normalization eliminates the need for relationships between tables.

• Normalization stores each piece of information multiple times for efficiency.

What are the potential drawbacks of over-normalization?

• Potential drawbacks of over-normalization include complexity, performance issues, and difficulties in data manipulation.

• Faster query execution

• Simplified data relationships

• Increased data redundancy

Can a table be in 2NF but not in 1NF? Why or why not?

• Yes, a table can be in 2NF but not in 1NF.

• No, a table cannot be in 2NF but not in 1NF.

• A table in 1NF can never be in 2NF.

• 2NF does not require 1NF as a prerequisite.

Provide an example of a functional dependency in a database.

• DepartmentID -> EmployeeName

• EmployeeName -> EmployeeID

• EmployeeID -> EmployeeName

• EmployeeID -> DepartmentID