Difference between primary key and unique key ?
Answer Posted / hemendra singh chaudhary
In the Table a primary key constraint column cannot holding
the null values.whereas unique constraint colum can holding
the null values.
Ex.|--------------------|
| ID(P) | Name(U) | #ID(P) ->It's a Primary Key
|--------------------| * Its a Not Null
| 1 | Hemendra | * A table Contain 1 Primary
| 2 | Neeraj | Key.
| 3 | PremJe | #Name(U)->It's a Unique Key
|NotNull |canbe Null| * Its can contain Null Value
|--------------------| * A table Contain more
than 1 unique Key.
Please Check the Radio Button..........
******************Gud Luck********************
Is This Answer Correct ? | 45 Yes | 0 No |
Post New Answer View All Answers
Explain oracle’s system global area (sga).
What is a relational database management system?
Select all the employees who were hired in last 2 years and who works in dept where max managers are working.
What are the oracle differences between nvl and coalesce
What is the scope of a local variable?
What is the string concatenation operator in oracle?
What is oracle datasource?
What is data block in Oracle?
What is the difference between substr & instr functions?
What is ordinary table in oracle?
Can we store images in oracle database?
Explain the difference between sap and oracle?
What happens if recursive calls get out of control?
How to delete multiple rows from a table in oracle?
What are the limitations of check constraint?