Difference between primary key and unique key ?
Answer Posted / ibrahim
PRIMARY KEY is identity of each row. UNIQUE KEY also
identity of each row.
PRIMARY KEY not accepts null values but unique can accept null.
but the core different between primary key and unique is we use primary key to link tow tables with each other but we can not use unique key to do this.
Is This Answer Correct ? | 1 Yes | 0 No |
Post New Answer View All Answers
HI Friends Myself Manoj,i am from bengaluru.i have 1 yr of exp in PLSQL but not upto the mark..now attending interviews but m not able to clear even 1 round..i have attended 3 interviews till today.purpose of writing this query is,i want to know the intreview topics that interviewer going to ask frequently,mainly SCENARIO based questions.IF anybody have any PLSQL projects please give it to me,it will helps me alot.Thanks for your patience.
What is the relation of a user account and a schema?
What is the difference between a hot backup and a cold backup in oracle?
How to retrieve data from an cursor to a record?
What is a cursor variable?
What is the implicit cursor in oracle?
How to connect to oracle using service name instead of sid?
How to experiment a data lock in oracle?
How many anonymous blocks can be defined?
How oracle handles dead locks?
What is a sub query and what are the different types of subqueries?
How to define a sub function?
Is oracle the best database?
What are the four Oracle system processes that must always be up and running for the database to be useable?
What are the differences between primary key and unique key?