Which of the following statements regarding primary key is false?

Options
- Primary key can not have null values
- Primary key may contain duplicate values
- Primary key can not be applied for multiple columns
- All of the above

CORRECT ANSWER : Primary key may contain duplicate values

Discussion Board
Primary key

Primary key may not contain duplicate values. Primary Key is a combination of Unique and NOT NULL Constraints so it can’t have duplicate values or any NULL values. A primary key is a special relational database table column (or combination of columns) designated to uniquely identify all table records. It must contain a unique value for each row of data.

Prajakta Pandit 02-6-2017 04:20 AM

"primary key may contains duplicate values" is also true

"primary key may contains duplicate values" is also true b'coz of initially deferred option in primary key constraint

Wajid 01-9-2015 09:01 AM

two corect answers

Primary key can be composite - made up of two or more columns. Thus the third option(Primary key can not be applied for multiple columns)(false) correct as well.

Nick 08-22-2014 04:50 PM

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