Insert random data to mongo

mongoload.php

<?php

include __DIR__ . '/vendor/autoload.php';

$faker = Faker\Factory::create();

$randData = [
    'gmt_diff' => 'randomDigitNotNull',
    'ios_id'   => 'uuid',
    'email'    => 'email',
    'string'   => 'word',
    'integ'    => 'randomDigitNotNull',
    'version'  => 'randomFloat',
];

function wtf($what)
{
    echo '<pre>';
    print_r($what);
    echo '</pre>';
}

function users()
{
    static $users = null;

    if ($users === null) {
        $users = (new Mongo())->selectCollection('mongoload', 'users');
    }

    return $users;
}

function get_random_data()
{
    global $faker, $randData;

    uksort($randData, function() { return rand() > rand(); });
    $rand = rand(2, 5);

    $data = [];
    for ($i = 0; $i <= $rand; $i++) {
        list($field, $method) = each($randData);
        $data[$field] = $faker->$method;
    }

    return $data;
}

for ($i = 0; $i < 1000; $i++) {
    $data = [];

    for ($j = 0; $j < 1000; $j++) {
        $data[] = get_random_data();
    }

    users()->batchInsert($data);
}

mysqlload.php

<?php

set_time_limit(600);

include __DIR__ . '/vendor/autoload.php';

$faker = Faker\Factory::create();

$randData = [
    'gmt_diff' => 'randomDigitNotNull',
    'ios_id'   => 'uuid',
    'email'    => 'email',
    'string'   => 'word',
    'integ'    => 'randomDigitNotNull',
    'version'  => 'randomFloat',
];

function wtf($what)
{
    echo '<pre>';
    print_r($what);
    echo '</pre>';
}

function db()
{
    static $db = null;

    if ($db === null) {
        $db = new PDO('mysql:host=127.0.0.1;dbname=mongoload', 'root', '', [PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES "UTF8"']);
    }

    return $db;
}

function get_random_data()
{
    global $faker, $randData;

    uksort($randData, function() { return rand() > rand(); });
    $rand = rand(2, 5);

    $data = [];
    for ($i = 0; $i <= $rand; $i++) {
        list($field, $method) = each($randData);
        $data[$field] = $faker->$method;
    }

    return $data;
}

function insert($data)
{
    global $randData;

    $fields = array_keys($randData);

    $sql = "INSERT INTO users (" . implode(', ', $fields) . ") VALUES";

    foreach ($data as $value) {
        $sql .= " (";

        foreach ($fields as $f) {
            if (array_key_exists($f, $value)) {
                $sql .= "'{$value[$f]}',";
            } else {
                $sql .= 'null,';
            }
        }

        // remove last comma
        $sql = substr($sql, 0, -1);

        $sql .= "),";
    }

    $sql = substr($sql, 0, -1);

    $stmt = db()->prepare($sql);
    $stmt->execute();
}

for ($i = 0; $i < 10000; $i++) {
    $data = [];

    for ($j = 0; $j < 50; $j++) {
        $data[] = get_random_data();
    }

    insert($data);
}