Interested to Buy Any Domain ? << Click Here >> for more details...
Is primary key = unique key,not null?
If yes,please explain
IF No,please explain
- 8 Answers
- 18025 Views
- Genpact, I also Faced
- E-Mail Answers
Answer Posted / chandrika
if we define unique key column to not null
then first attempt it not allow to insert null value in
column but after inserting once we can edit its value to
null even if it is not null ( means its allow null)
if we assign primary key then its not allow (in every
situation it not allow null and duplication)
that is main difference between unique key and primery key
| Is This Answer Correct ? | 0 Yes | 7 No |
Post New Answer View All Answers
Where is the export dump file located?
What are the numeric comparison operations?
How to create a temporary table in oracle?
What is a system tablespace?
Is there a combination of "like" and "in" in sql?
How to use "in" parameter properly?
How to see the table columns used in an index?
What are the four Oracle system processes that must always be up and running for the database to be useable?
How does one get the view definition of fixed views/tables?
What is a cursor variable?
How to create a new table in oracle?
Explain what are clusters?
What is an index associated with a constraint?
What is oracle latest version?
Illustrate how to determine the amount of physical CPUs a Unix Box possesses (LINUX and/or Solaris).
