CODEWITHSUNDEEP
phpmysqlpdo
MohamedSalem
MohamedSalem

Reputation: 45

Prevent duplicate data in Mysql with php

I create simple a Registration Form that connect with mysql

html code :

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <link href="css/bootstrap.min.css" rel="stylesheet">
</head>
<body>
    
    <div class="container">

<form method="post" enctype="multipart/form-data>">
<div class="form-group">

<label for="username"> User Name</label>
<input type="text" name="username" id="username">
</div>
<br>
<div class="form-group">
<label for="password"> password</label>
<input type="password" name="password" id="password">
</div>
<br>
<div class="form-group">
<label for="age"> Age</label>
<input type="text" name="age" id="age">
</div>
<br>

<button class="btn btn-primary btn-block" name="b_send"> send data</button>

</form>



</div>

    <script src="js/bootstrap.min.js"></script>
    <script src="js/jquery.js"></script>

</body>
</html>

mysql : dbname is = final table is = students

in table students i have column (username) and i set it to UNIQUE ,

in php code i make connection :

    <?php
    
if ($_SERVER['REQUEST_METHOD']=="POST"){

    if(isset($_POST['b_send'])){

        $username= $_POST['username'];
        $password=$_POST['password'] ;
        $age=$_POST['age'];
        
            try{
$conn=new PDO ("mysql:host=localhost; dbname=final",
                "admin","admin");
                
$sendvalues=$conn->exec("insert into students(username,password,age)
                        values('$username','$password','$age')"); 
                                                                                        

}

catch(PDOExeption $e){

    echo "error in data send";

}
         

}

}

?>

now , i want to make check , if user has enter duplicate name that already exist in column (username), it prevent sending data to db and give user error message

thanks in advance

Upvotes: 0

Views: 288

Answers (1)

noah1400
noah1400

Reputation: 1509

Either your keep using insert into and catch an error if one occured while executing the query like this:

try {
   $conn->exec("insert into students(username,password,age)
                        values('$username','$password','$age')"); 
   // do other things if successfully inserted
} catch (PDOException $e) {
   if ($e->errorInfo[1] == 1062) {
      // duplicate entry, do something else
   } else {
      // an error other than duplicate entry occurred
   }
}

Because you set the column username to UNIQUE the execution will throw an error when trying to insert a duplicate entry.

or you can use insert ignore and completely ignore an error message. read more about insert ignore here

Upvotes: -2

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