Golgappa.net | Golgappa.org | BagIndia.net | BodyIndia.Com | CabIndia.net | CarsBikes.net | CarsBikes.org | CashIndia.net | ConsumerIndia.net | CookingIndia.net | DataIndia.net | DealIndia.net | EmailIndia.net | FirstTablet.com | FirstTourist.com | ForsaleIndia.net | IndiaBody.Com | IndiaCab.net | IndiaCash.net | IndiaModel.net | KidForum.net | OfficeIndia.net | PaysIndia.com | RestaurantIndia.net | RestaurantsIndia.net | SaleForum.net | SellForum.net | SoldIndia.com | StarIndia.net | TomatoCab.com | TomatoCabs.com | TownIndia.com
Interested to Buy Any Domain ? << Click Here >> for more details...

Difference between primary key and unique key ?

Answer Posted / tom

There is two difference between them.

1. The not null constraint is by default added to primary
key, it means, primary key attribute cannot accept null
values, whereas, the attribute declared as unique can accept
null values. It is the major difference between the two.

2. Secondly, we can have only one primary key in a relation,
whereas, multiple attributes can be declared unique at the
same time.

Is This Answer Correct ?    1 Yes 0 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

How to resolve the ORA-39133 error in Oracle?

1033


How do we represent comments in oracle?

1003


1) Does oracle have any table which contain all the exceptions and it's code internally?

1698


How to compare dates in oracle sql?

1043


how can we store any pdf file in oracle

2096


How to view existing locks on the database?

999


What are the different windows events activated at runtime ?

2834


How to use null as conditions in oracle?

1003


How can we view last record added to a table?

972


How to create tables for odbc connection testing?

1011


src name sex a,male b,female c,male d,female Required output : male female a,b c,d tried pivot but was not successfull select * from src pivot (max(name) for sex in ('MALE','FEMALE'));

1617


What is a subquery?

1058


What is the difference between PFILE and SPFILE in Oracle?

996


What is user managed backup in Oracle?

1078


Explain implicit cursor.

962