Java & MySQL - Unique Key not working?

Question

I'm using the MySQL Workbench, and assigned one of my columns as a Unique Key. When I check the MySQL table, it still enters duplicates for "users_name" I'm still new to MySQL/Java, so I'm sure I'm just making a silly mistake.

System.out.print("Name: ");
String name = sc.nextLine();
System.out.print("Password: ");
String pass = sc.nextLine();

String SQL = String.format("INSERT INTO users (users_name, users_password) values('" + name + "','" + pass + "')");
PreparedStatement stmt = (PreparedStatement) connection.prepareStatement(SQL);
stmt.executeUpdate(SQL);

MySQL Table Definition:

CREATE  TABLE IF NOT EXISTS `mydb`.`users` (
`users_id` INT NOT NULL AUTO_INCREMENT ,
`users_name` VARCHAR(45) NULL ,
`users_password` VARCHAR(45) NULL ,
PRIMARY KEY (`users_id`) ,
UNIQUE INDEX `users_id_UNIQUE` (`users_id` ASC) ,
UNIQUE INDEX `users_name_UNIQUE` (`users_name` ASC) )
ENGINE = InnoDB

@JonathonCharlesLoch: It means please show the sql statment that created your table. something like: create table users(id int... — juergen d
– juergen d, Commented Mar 3, 2013 at 1:58

jlordo · Accepted Answer · 2013-03-03 02:01:41Z

2

Not really an answer, but very helpful advice:

This is how you should use your PreparedStatement:

String sql = "INSERT INTO users (users_name, users_password) values (?, ?);";
PreparedStatement stmt = connection.prepareStatement(sql);
stmt.setString(1, name);
stmt.setString(2, pass);
stmt.executeUpdate();

To answer your actual question, we need to see the table definition.

answered Mar 3, 2013 at 2:01

jlordo

37.9k7 gold badges63 silver badges84 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Philip Tenn Over a year ago

+1 definitely don't String-concat in the values of your PreparedStatement as OP has in the code snippet above.

Jonathon Charles Loch Over a year ago

Well, I made a new table, with the same Primary Keys, Uniques, Auto Increments, etc. And now it works. Guess something didn't work last time.

Collectives™ on Stack Overflow

Java & MySQL - Unique Key not working?

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related