the above answer is wrong ...we can use foreign key for unique key also..

IN A TABLE HAVE ONE COLUMN PRIMARY KEY..IT WILL NOT ALLOWS
NULL VALUES AND DUPLICATE VALUES..INSTEAD OF PRIMARY KEY
WHY CANT WE USE UNIQUE AND NOT NULL.THESE TWO ALSO DOESNT
ACCEPT NULL VALUES IN NOT NULL AND UNIQUE DOESNT ACCEPT
DUPLICATE VALUES?
SO WHAT IS THE DIFEERENCE BETWEEN(UNIQUE,NOT NULL) AND
PRIMARY KEY??????

Question Posted / shahid

8 Answers
10457 Views
rsystems, I also Faced
E-Mail Answers

Answer Posted / shahid

the above answer is wrong ...we can use foreign key for
unique key also...

Is This Answer Correct ?

8 Yes

2 No

Post New Answer View All Answers

Please Help Members By Posting Answers For Below Questions

Can we use update in sql function?

1053

Is mariadb a nosql database?

1042

What is pls integer?

1026

How do I turn a list into a table?

953

What is materialized view in sql?

915

What is varchar used for?

1074

What is scalar function?

1045

How do I count rows in sql?

996

Why do we need cursors in pl sql?

1071

Is grant a ddl statement?

894

Can variables be used in sql statements?

1027

What are actual parameters and formal parameters?

1101

Is delete faster than truncate?

1002

What is the limitation on the block size of pl/sql?

980

What are sql built in functions?

933