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


Please Help Members By Posting Answers For Below Questions

How to assign a tablespace to a users in oracle?

786


What is the exact use of Collections?

1896


Explain parameter file in oracle.

779


can u send the sql dumps to sivakumarr1987@gmail.com plz help me

2794


How to delete all rows a table in oracle?

811


What do you understand by a database object? Can you list a few of them?

785


How to define a specific record type?

836


What is Library Cache in Oracle?

847


Which is faster join or subquery in oracle?

728


Explain the characteristics of oracle dba?

864


What happens if variable names collide with table/column names?

837


candidate key is subset of super key but not vice-verse explain

1784


How to convert raw data type into text in oracle? Explain

792


What are the predefined tablespaces in a database?

768


What is the parameter mode that can be passed to a procedure?

802