Interested to Buy Any Domain ? << Click Here >> for more details...
What is difference between UNIQUE constraint and PRIMARY KEY
constraint ?
- 3 Answers
- 7492 Views
- I also Faced
- E-Mail Answers
Answer Posted / naren
When ever you create a primary key constraint on perticular
column in a table it creates clustered index by default,
it cannot allow null values and a table having only one
primary key constraint. But in the case of Unique Key
constraint, it allow only one null value, it creates non-
clustered index by default and a table having multiple
unique key constraints.
Regards
Naren Krishna
| Is This Answer Correct ? | 8 Yes | 3 No |
Post New Answer View All Answers
How to define a data field as not null?
What do the 9i dbms_standard.sql_txt() and dbms_standard.sql_text() procedures do?
What suggestions do you have to reduce the network traffic?
What are the benefits of ordbms?
What are the differences between primary key and unique key?
What is merge statement used for?
How to shutdown your 10g xe server?
A table t is there.If you perform insert ,update and delete then the trigger will fire.What is the minimum no of trigger required for a table.
what is insert all statement in sql
What is MTTR advisor in Oracle?
candidate key is subset of super key but not vice-verse explain
Difference between cartesian join and cross join?
How can windows applications connect to oracle servers?
How to define a sub function?
what is the use of system.effective.date variable in oracle?
