Question

Which of the following is a correct statement about primary keys?

1) The data values of a primary key must be different (i.e., unique).
2) A primary is always another table's foreign key.
3) A primary cannot be used in another table as a foreign key.
4) Most tables in a database may not require primary keys.

Answer 1

The correct statement about primary keys is that their data values must be unique, which enables them to uniquely identify each record in a database table. The other statements are inaccurate regarding the usage and necessity of primary keys in relational databases.

Step-by-step explanation:

The correct statement about primary keys is the first option: 1) The data values of a primary key must be different (i.e., unique). Primary keys are a fundamental aspect of relational databases, and their main function is to uniquely identify each record in a database table.

The other statements provided are incorrect because:

• 2) A primary is always another table's foreign key. - This is not accurate. While a primary key can be used as a foreign key in another table to create a relationship, it is not always used as such.
• 3) A primary cannot be used in another table as a foreign key. - This statement is incorrect because primary keys are often used as foreign keys in other tables to establish relationships.
• 4) Most tables in a database may not require primary keys. - This is misleading because nearly all database tables should have a primary key to ensure data integrity and enable efficient querying.