Difference between primary key and unique key ?
Answer Posted / jeyasree
* Only one primary key is allowed per table (any number of
unique keys are allowed).
* Primary key columns automatically become NOT NULL (unique
keys can contain nulls).
* UNIQUE and DISTINCT are synonymous in a SELECT list.
| Is This Answer Correct ? | 82 Yes | 45 No |
Post New Answer View All Answers
various types of hints and their usage
How to view existing locks on the database?
How to run the anonymous block again?
What are the differences between primary key and unique key?
What is meant by an index?
What is data file?
How to rename a tablespace in oracle?
Which is faster join or subquery in oracle?
How to best split csv strings in oracle 9i?
How do I find my oracle client driver version?
Difference between oracle's plus (+) notation and ansi join notation?
Can we store pictures in the database and if so, how it can be done?
What are the types of partitions in oracle?
What are advantages of dateset in datastage?
definition of cluster and non-clustered index?