Difference between primary key and unique key ?
Answer Posted / sripathi venkata ramesh
I am Sripathi Venkata Ramesh from Gudivada and the answer
is mentioned below
Primary key: A Primary key is a column or group of columns
used to uniquely identify each row in a table like
It defines the column as a Mandatory column.
The data held across the column must be unique.
By default it creates clustered index.
It does not allow null values and duplicate values
Unique key: It also for the record uniqueness.
It allows only one null value
By default it creates non clustered index
| Is This Answer Correct ? | 3 Yes | 1 No |
Post New Answer View All Answers
Can we write insert statement in function in oracle?
What is sequence?
What is the fastest query method to fetch data from the table?
Can we convert a date to char in oracle and if so, what would be the syntax?
Explain the use of indexes option in imp command.
What is a select query statement in oracle?
Explain the use of constraints option in exp command.
How to get a create statement for an existing table?
Please explain oracle data types with examples?
Difference between hot backup vs. Cold backup?
How do I limit the number of oracle database connections generated by weblogic server?
In not less than 100 words what's the main difference between Rolap and Molap in ORACLE ?
How to define an oracle cursor variable?
what is reindexing?
How to invoke the data pump import utility?