Computer Science for IGCSE & O level - Databases (Section 3 - No. 12)
What is the purpose of the 'UNIQUE' constraint in a database?
To ensure a field must contain a value.
To prevent duplicate values in a column.
To define the primary key for a table.
To create a foreign key relationship.
คำอธิบาย
The UNIQUE constraint ensures that values in a column are unique.