Answer / venkat rao

Unique key takes null value but primary key doesnot take
null value
primary key have properties of both null key and unique key
constraints

Answer / sudhanshu_kmr

.....primary key.......... unique key

at most one column .....:... any number of column

only unique values........... only unique values

don't accept null........... accept null

Answer / ashish asthana

Primay key restrict the duplicacy in the records and does
not accept null value or there are only one primary key in
a table

Unique constraint also restict the duplicacy but it accept
the null value one or more then one. We can apply unique
constraint more than one column

Answer / durai

primary key is does not allow duplicate which is contain not
null it is only once we can use in table

unique key allow null value

Answer / pradeep rajpoot

primary key no null value allow.
but unique key one null value is allow

Can we write pl sql mysql?

0 Answers  

what is the main difference between myisam and innodb

2 Answers   Wipro,

What is database url for mysql?

0 Answers  

How do I rename a table in mysql?

0 Answers  

What happens when the column is set to AUTO INCREMENT and if you reach maximum value in the table?

0 Answers  

How many mysql connections can handle?

0 Answers  

please give me the answer for this: query which generates the second highest integer in the table?

8 Answers  

How to see the database architecture in MySQL??

3 Answers  

Write a command to view mysql database table structure?

0 Answers  

Ondelete clause is specified with a.)Drop table b.)Delete command c.)Create table d.)Select command

5 Answers   Amdocs, MediaSoft,

Why mysql is open source?

0 Answers  

What is normalization and list the different types of normalization?

0 Answers