Join the social network of Tech Nerds, increase skill rank, get work, manage projects...
 
  • Primary Key

    • 0
    • 0
    • 0
    • 0
    • 0
    • 0
    • 0
    • 0
    • 198
    Comment on it

    Primary Key

    A primary key in a table is a unique key that is the element in this column are unique and can not be null.

    It is used to mantain the integrity.

    It uniquely identify the row in the table.

    It is a constraint on the table.

    It can not have more than 16 columns.

    It can also be a group of columns.

    CREATE TABLE CUSTOMERS(
           ID   INT              NOT NULL,
           NAME VARCHAR (20)     NOT NULL,
           AGE  INT              NOT NULL,
           ADDRESS  CHAR (25) ,
           SALARY   DECIMAL (18, 2),       
           PRIMARY KEY (ID)
    );
    

 0 Comment(s)

Sign In
                           OR                           
                           OR                           
Register

Sign up using

                           OR                           
Forgot Password
Fill out the form below and instructions to reset your password will be emailed to you:
Reset Password
Fill out the form below and reset your password: