Answer:
A. Multi-field attributes
B. A ternary relationship
C. A unary relationship
Answer:
d. A many-to-many relationship
Explanation:
A composite primary key is the key that uses two or more attributes to uniquely identify any row in a table. These are usually used in associative entity table in which many to many relationship between 2 or more other table exists.
Example:
Suppose we have a table which consists of 4 columns:
student_ID, subject_ID, subject_name and marks.
Here the student_ID and subject_ID can be combined together to form the composite primary key.
