Difference between primary key and unique key ?
Answer Posted / mudigouda patil
PRIMARY KEY
1)TABLE CAN NOT HAVE MORE THAN ONE PRIMARY KEY.
2)PK DOES NOT ALLOW NULL VALUES.
UNIQUE KEY
1)TABLES CAN HAVE MORE THAN ONE UNIQUE KEY.
2)UNIQUE KEY ALLOWS NULL VALUES.
| Is This Answer Correct ? | 0 Yes | 1 No |
Post New Answer View All Answers
What is index-organized table in Oracle?
What spfile/init.ora file parameter exists to force the CBO to make the execution path of a given statement use an index, even if the index scan may appear to be calculated as more costly?
How to open a cursor variable?
What is a subquery in oracle?
What is ordinary table in oracle?
What is rowid and rownum in oracle?
ABOUT IDENTITY?
What is a tns service name?
Explain the dml?
List the parts of a database trigger.
What is the difference between primary key and unique key and foreign key in oracle?
How to create a new tablespace in oracle?
Point the difference between translate and replace?
What are the roles of dba?
What are the different pseudo commands? Explain in general?