When we can declare a column as Unique and Not Null both at
the same time. What is the use pf Primary Key then?
Answer Posted / swapna
The concept of adding an unique key and not null constraint
to a column as well as adding as unique index to it , you
will assume to get the benefits of adding an primary key
to that column.
But use it for the purpose of referential integrity will
not allow to do so.
That's what PK is so useful. You will use it for
normalization purpose.
| Is This Answer Correct ? | 12 Yes | 6 No |
Post New Answer View All Answers
How to make a copy values from one column to another in sql?
Is not null in sql?
what is 'mysqldump'? : Sql dba
what is not null constraint? : Sql dba
What is the difference between pl and sql?
Can primary key be changed?
What are stuff and replace function?
Is pl sql a scripting language?
What is null in pl/sql?
What are the benefits of pl sql?
What are inner outer left and right joins in sql?
What is the reports view in oracle sql developer?
what is a constraint? : Sql dba
What does where 1/2 mean in sql?
What are the types of views in sql?