Difference between primary key and unique key ?
Answer Posted / vaithianathan
primary key not accepts null value and
not allows duplicate values.
but Unique key not allows duplicate values
but it accepts ONLY ONE NULL VALUE.
only one primary key allowed per table
we can create multiple unique keys
on the table
By Default, Primary key creates Clustered Index and Unique key Creates Non Clustered Index
| Is This Answer Correct ? | 3 Yes | 0 No |
Post New Answer View All Answers
What is an oracle and why it is used?
From the following identify the non schema object: packages, triggers, public synonyms, tables and indexes.
How to put more than 1000 values into an oracle in clause?
What are the major difference between truncate and delete?
what are bitmap indexes? How does they work?
What are the oracle differences between nvl and coalesce
Hi this srilatha. I comlpeted my Oracle-hrms. can u provide me interview questions on Core hr, payroll,sshr,OLM etc..
What is the difference between sharding and partitioning?
What is a private synonym?
How do you find out from the RMAN catalog if a particular archive log has been backed-up?
How does oracle handle read consistency?
Explain the use of record option in exp command.
what is the difference between substr and instr function in oracle?
hi friends i completed b.com 2004.i have 3y accounting exp. in manufacturing company.now i have completed oracle finance.pls suggest me how will get job in oracle.can i get job in oracle.
What is oracle used for?