2NF relations are those that are in 1NF with all the attribute types dependent on the ___ key.a.Compositeb.Primaryc.Foreignd.Alternate

Break Down the Problem

1. Identify the definitions of 1NF and 2NF.
2. Understand the types of keys that can be used in database relations.
3. Determine which key is relevant for 2NF.

Relevant Concepts

• 1NF (First Normal Form): A relation is in 1NF if it contains only atomic (indivisible) values and each entry in a column is of the same kind.
• 2NF (Second Normal Form): A relation is in 2NF if it is in 1NF and all non-key attributes are fully functionally dependent on the primary key.

Analysis and Detail

1. Primary Key: This is the main key that uniquely identifies each record in a relation. In 2NF, every attribute must depend on this key to avoid redundancy.
2. Composite Key: A key that consists of two or more attributes used together to uniquely identify an entity.
3. Foreign Key: An attribute that creates a relationship between two tables, referring back to the primary key in another table.
4. Alternate Key: Any candidate key that is not the primary key.

Verify and Summarize

Since 2NF requires that all attributes depend entirely on the primary key, the correct option is:

Final Answer

b. Primary