what is the difference between primary key & foreign key?

Answer Posted / anjanareddy

i cleared this question simple.

TAKE A LOOK

primary key:-It doesn't allow NULL values and duplicate values
it is a unique one.


Foreign key:- It allows NULL and duplicate values
It always give reference to primary key of another table

Is This Answer Correct ?    1 Yes 0 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

Explain constraining triggers.

593


What is tns service name?

617


How can I see all tables in oracle?

539


What is oracle data type?

553


Which is better Oracle or MS SQL? Why?

3970






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?

930


How would you begin to troubleshoot an ORA-3113 error?

1601


Can we store pictures in the database and if so, how it can be done?

587


How to estimate disk space needed for an export job?

558


How to initialize variables with default values?

634


What is the data type of dual table?

524


Explain oracle’s server parameter file.

564


What suggestions do you have to reduce the network traffic?

541


Explain the difference between replace() and translate() functions in oracle?

577


How to declare a local variable?

592