将唯一值插入 MySQL 表

Question

I have a table named leads with one column named id , it is not a primary key and not auto incremented. I want to take the maximum id and increment it to insert new id.
This is my approach. (I do this for testing)

<?php
for($i=1; $i<1000; $i++){

    \DB::beginTransaction();
    \DB::raw('LOCK TABLES leads WRITE');
    // Get maximum id
    $max = (int)\DB::table('leads')->max('id');

    \DB::table('leads')->insert([
        'id'=>str_pad(++$max, 10, '0', STR_PAD_RIGHT) // Make 10 digit id
    ]);

    \DB::raw('UNLOCK TABLES');
    \DB::commit();

}
?>

When I execute this code at once, the id does not being duplicate. But when I hit this route from multiple browser at a time, the id gets duplicate. How can I resolve the problem without make the column AUTO_INCREMENT?

Answer 1

I suggest using AUTO_INCREMENT . but if you don't want you can insert multi record to avoid duplicate same as :

<?php

\DB::beginTransaction();
// Get maximum id
$max = (int)\DB::table('leads')->max('id');
\DB::raw('LOCK TABLES leads WRITE');
for($i=1; $i<1000; $i++){
    $data[] = [
        'id'=>str_pad(++$max, 10, '0', STR_PAD_RIGHT) // Make 10 digit id
    ]
}
\DB::table('leads')->insert($data);
\DB::raw('UNLOCK TABLES');
\DB::commit();
?>

I think it's best to use AUTO_INCREMENT , locking the table in this case will degrade performance and cause some unwanted effects. If you want the same format as str_pad, you can use laravel's Defining A Mutator