What term is used to refer to the main key that is referenced within a foreign key relationship?

In the context of foreign key relationships in databases, the term used to refer to the main key that is referenced is known as the parent key. The parent key, which is typically a primary key in a parent table, establishes a relationship with a foreign key located in a child table. This relationship ensures that each value of the foreign key corresponds to a valid entry in the parent table, thus maintaining referential integrity.

The primary key serves as a unique identifier for records within a table, while the foreign key in the child table references this primary key, creating a link between the two tables. By referencing the parent key, the database can enforce rules about how data is related and ensure that no orphan records exist in the child table.

Regarding the other choices, the primary key is essentially a unique identifier but does not directly refer to its role in a relationship context as the term "parent key" does. Null does not pertain to key relationships and typically represents the absence of data. An intermediate entity is a concept used in certain database designs, especially in many-to-many relationships, but it does not specifically describe the main key being referenced in a foreign key relationship. Therefore, identifying the parent key is crucial for understanding how these relationships function and are structured within