Question

A column whose value is always unique in every row in a table is called a(n) _____.

a) Primary key
b) Foreign key
c) Index
d) Constraint

Answer 1

The unique identifier for each row in a database table is called a primary key, which ensures that no two rows have the same value for this column. A primary key differs from a foreign key, index, or constraint.

Step-by-step explanation:

A column whose value is always unique in every row in a table is called a primary key. The correct answer to the question is option a) Primary key. A primary key is a specific type of table column that is used to uniquely identify each row in a database table. No two rows can have the same primary key value, ensuring each record is easily identifiable. This is distinct from a foreign key, which is used to link two tables together, an index, which is a performance optimization feature that can include multiple columns, and a constraint, which is a rule applied to the data in the table.