I have used this script and I created a table in mysql

CREATE TABLE `employee` (

`id` int(3) NOT NULL AUTO_INCREMENT,

`first_name` varchar(20) DEFAULT NULL,

`last_name` varchar(20) DEFAULT NULL,

`username` varchar(250) DEFAULT NULL,

`password` varchar(20) DEFAULT NULL,

`address` varchar(45) DEFAULT NULL,

`contact` varchar(45) DEFAULT NULL,

PRIMARY KEY (`id`)

) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

And this is my class to connect mysql and get the values from the user

public class EmployeeDao {

public int registerEmployee(Employee employee) throws ClassNotFoundException {

String INSERT_USERS_SQL = "INSERT INTO employee" +

" (id, first_name, last_name, username, password, address, contact) VALUES " +

" (?, ?, ?, ?, ?,?,?);";

int result = 0;

Class.forName("com.mysql.cj.jdbc.Driver");

try (Connection connection = DriverManager

.getConnection("jdbc:mysql://localhost:3306/employees?allowPublicKeyRetrieval=true&useSSL=false", "root", "root");

// Step 2:Create a statement using connection object

PreparedStatement preparedStatement = connection.prepareStatement(INSERT_USERS_SQL)) {

preparedStatement.setInt(1, 1);

preparedStatement.setString(2, employee.getFirstName());

preparedStatement.setString(3, employee.getLastName());

preparedStatement.setString(4, employee.getUsername());

preparedStatement.setString(5, employee.getPassword());

preparedStatement.setString(6, employee.getAddress());

preparedStatement.setString(7, employee.getContact());

System.out.println("Successful");

System.out.println(preparedStatement);

// Step 3: Execute the query or update query

result = preparedStatement.executeUpdate();

} catch (SQLException e) {

System.out.println("fail");

// process sql exception

printSQLException(e);

}

return result;

}

Mysql suppose to generate unique Primary key for every row but I can insert (first_name,last_name,username,password,address,contact ) for first row and when i tried second I'm getting Duplicate entry '1' for key 'employee.PRIMARY'. I though AUTO_INCREMENT generate unique PK for every row. I would appreciate for help.

This is how the user enter values:

Employee Register Form First Name Last Name UserName Password Address Contact No Submit