Difference between primary key and unique key ?
Answer Posted / anand b
Primary Key : Is an identity of a row, Only one primary key per table, No duplicate values allowed, & No NULL values are allowed.
Unique Key : Its values are unique, It can contain any number of NULL values unless combination is going to be unique.
Is This Answer Correct ? | 1 Yes | 2 No |
Post New Answer View All Answers
How can you use check constraints for self referential integrity?
Explain overloading. Can functions be overloaded?
What is translate in oracle?
Is truncate autocommit in oracle?
Can any one explain me when i execute below query.. select months_between('07-JUL-12','10-FEB-12') from dual; Out put:- 4.90322581 How oracle calculate?
What are the different types of failures that occur in Oracle database?
Explain integrity constraint?
what are bitmap indexes? How does they work?
What is the difference between formal parameters and actual parameters?
What is data block in Oracle?
what is the difference between substr and instr function in oracle?
How to name query output columns in oracle?
How to fetch the row which has the max value for a column?
What is concurrency in oracle?
Can we store images in oracle database?