DB Development Question: Download DB Development PDF
What is difference between primary key and unique key?
Answer:
Basic difference between primary key and unique is that primary key is used to define a table in other tables for preventing data from anomalies,and unique key is used in a table to apply unifications among different values or columns of a tables and only in that table obviously.Their is no usage of unique key outward a table but primary key is often used to make relations between other tables.
| Previous Question | Next Question |
| How to find the first two highest salaries in deptno in emp table? | What is the use of foreginkey? |