Difference between primary key and unique key ?
Answer Posted / umapathy.r
The column holding the primary key constraint cannot accept
null values.whereas colum holding the unique constraint can
accept null values assume that t3 is a table with two
columns t1 having primary key constraint and t2 having
unique constraint if u try to insert null into t2 it will
accept that values whereas column t1 will not accept null
| Is This Answer Correct ? | 1164 Yes | 121 No |
Post New Answer View All Answers
Explain the use of consistent option in exp command.
Explain the use of record option in exp command.
What are the differences between lov and list item?
What is open database communication (odbc) in oracle?
How to write text literals in oracle?
List the various oracle database objects?
How to define a cusotmer as a supplier in ORACLE R12
How to execute a stored program unit?
How to speed up webrick?
How to revoke create session privilege from a user in oracle?
Why does oracle 9i treat an empty string as null?
how to handle exceptions in post production
How to create a single index for multiple columns?
What happens in oracle commit?
Describe the types of sub query?