osekaiDB.php

<?php
class Database
{
    private static $db;
    private $connection;

    private function __construct()
    {
        $this->connection = new MySQLi('localhost', 'user', 'password', 'database');
        $this->connection->set_charset("utf8mb4"); // to fix emojis in comments
    }

    function __destruct()
    {
        $this->connection->close();
    }

    public static function getConnection()
    {
        if (self::$db == null) {
            self::$db = new Database();
        }
        return self::$db->connection;
    }

    /**
     * @param string $strQuery
     * @param string $strTypes
     * @param array $colVariables
     * 
     * @return array
     */
    public static function execSelect($strQuery, $strTypes, $colVariables)
    {
        $mysql = self::getConnection();
        $stmt = $mysql->prepare($strQuery);
        $stmt->bind_param($strTypes, ...$colVariables);
        $stmt->execute();
        $meta = $stmt->result_metadata();

        while ($field = $meta->fetch_field()) $params[] = &$row[$field->name];
        $stmt->bind_result(...$params);
        while ($stmt->fetch()) {
            foreach ($row as $key => $val) {
                $c[$key] = $val;
            }
            $hits[] = $c;
        }
        if ($mysql->more_results()) {
            $mysql->next_result();
        }
        if (isset($hits)) {
            return $hits;
        } else {
            return [];
        }
        return (array)$hits;
    }

    /**
     * @param string $strQuery
     * 
     * @return array
     */
    public static function execSimpleSelect($strQuery)
    {
        $oQuery = self::getConnection()->query($strQuery);
        while ($val = $oQuery->fetch_assoc()) {
            $hits[] = $val;
        }
        return $hits;
    }

    /**
     * @param string $strQuery
     * @param string $strTypes
     * @param array $colVariables
     * 
     * @return void
     */
    public static function execOperation($strQuery, $strTypes, $colVariables): void
    {
        $mysql = self::getConnection();
        $stmt = $mysql->prepare($strQuery);
        $stmt->bind_param($strTypes, ...$colVariables);
        $stmt->execute();
    }

    /**
     * @param string $strQuery
     * 
     * @return void
     */
    public static function execSimpleOperation($strQuery): void
    {
        $mysql = self::getConnection();
        $stmt = $mysql->prepare($strQuery);
        $stmt->execute();
    }
}