what is the difference between unique and primary key

Answer Posted / divyarao

primary key accepts only values which has no duplication ,and does not accept null values . for a a table there should be only one primary key constraint.
whereas in unique key ,it accepts null values .here also there should not be any duplication ,a table may have more than one unique key constarint

Is This Answer Correct ?    0 Yes 0 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

What are fact tables and dimension tables ? What is dimensional modeling and star schema design

516


What is query in rdbms?

581


What is snow flake schema design in database? What's the difference between star and snow flake schema?

528


What are functions in database?

602


What the default privileges which get assigned ?

571






What are the advantages of database management system?

536


How can I join two tables in database?

608


What is bcnf standard form in dbms?

624


How do I create a database in open office?

592


What are the types of database users?

591


Why are databases so important?

560


What's the difference between clustered and non-clustered indexes?

563


What do you understand by aggregation and atomicity?

596


What do you mean by entity type extension?

617


What are the characteristics of database?

561