Home >> MySql >> What is primary key in MySql

What is primary key in MySql

1-Primary key is one or more columns in a table used for uniquely identify every row in the table.

2-Primary key will not allow duplicates values.

3-Primary key will not allow NULL values.

4-Only one primary key in a table.

5-Primary key cannot be LONG data types.

6-Unique index created automatically.

Post Your Comment

Next Questions
What is unique key
What is foreign key
What is join
What is cross join
What is natural join
What is outer join
What is self join
What is aggregate function
COUNT(*) aggregate function
AVG() aggregate function
MIN() aggregate function
MAX() aggregate function
SUM() aggregate function
STDED() aggregate function
CONCAT() function
GROUP_CONCAT() function
CONCAT_WS() function
CHECKSUM_AGG() aggregate function
ABS(n) aggregate function
POWER(m,n) aggregate function
ROUND() aggregate function
SQRT() aggregate function
GREATEST() aggregate function
LEAST() aggregate function
EXP() aggregate function

Copyright ©2022 coderraj.com. All Rights Reserved.