Concepts and Architecture Question: Download Questions PDF
Tell me what is difference between UNIQUE constraint and PRIMARY KEY constraint?
Answer:
A column defined as UNIQUE can contain Nulls while a column defined as PRIMARY KEY can't contain Nulls.Unique key cannot be used to create referential integrity whereas primary key can do.
Download Oracle Architecture and Concepts Interview Questions And Answers
PDF
| Previous Question | Next Question |
| Tell me what are the uses of Rollback Segment? | Explain what are the Limitations of a CHECK Constraint? |