Question
Given the following table:
| ID | Month | Day | Year | Name |
|---|---|---|---|---|
| 1 | October | 6 | 1969 | James |
| 2 | May | 13 | 1970 | Jane |
| 3 | September | 25 | 1999 | John |
| 4 | April | 15 | 1976 | Helena |
Which of the following fields best represents a primary key?
- A. ID Correct
- B. Month
- C. Day
- D. Year
- E. Name
Explanation
A primary key must uniquely identify each row and never repeat or be empty, and the sequential ID field is designed for exactly that. Month, day and year values can be shared by many people, and names are not guaranteed to be unique either, so none of them can reliably identify a single record.
