In the context of developing a CMS, what are some considerations for creating global classes or toolkits to support different database standards or file systems in PHP?

// Example of creating a Database class that abstracts away the specific database implementation

class Database {
    private $connection;

    public function __construct($dbType, $host, $username, $password, $dbName) {
        switch($dbType) {
            case 'mysql':
                $this->connection = new mysqli($host, $username, $password, $dbName);
                break;
            case 'postgresql':
                $this->connection = new PDO("pgsql:host=$host;dbname=$dbName", $username, $password);
                break;
            // Add support for other database types here
        }
    }

    public function query($sql) {
        // Execute query using the appropriate database connection
    }

    // Add other database operations here
}

// Example of creating a Filesystem class that abstracts away the specific file system implementation

class Filesystem {
    private $filesystem;

    public function __construct($fsType, $basePath) {
        switch($fsType) {
            case 'local':
                $this->filesystem = new LocalFilesystem($basePath);
                break;
            case 's3':
                $this->filesystem = new S3Filesystem($basePath);
                break;
            // Add support for other file system types here
        }
    }

    public function read($path) {
        // Read file using the appropriate file system implementation
    }

    // Add other file system operations here
}