Nette\Caching\Storages\SQLiteJournal::open PHP Method

    private function open()
    {
        if (!extension_loaded('pdo_sqlite')) {
            throw new Nette\NotSupportedException('SQLiteJournal requires PHP extension pdo_sqlite which is not loaded.');
        }
        if ($this->path !== ':memory:' && !is_file($this->path)) {
            touch($this->path);
            // ensures ordinary file permissions
        }
        $this->pdo = new \PDO('sqlite:' . $this->path);
        $this->pdo->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
        $this->pdo->exec('
			PRAGMA foreign_keys = OFF;
			PRAGMA journal_mode = WAL;
			CREATE TABLE IF NOT EXISTS tags (
				key BLOB NOT NULL,
				tag BLOB NOT NULL
			);
			CREATE TABLE IF NOT EXISTS priorities (
				key BLOB NOT NULL,
				priority INT NOT NULL
			);
			CREATE INDEX IF NOT EXISTS idx_tags_tag ON tags(tag);
			CREATE UNIQUE INDEX IF NOT EXISTS idx_tags_key_tag ON tags(key, tag);
			CREATE UNIQUE INDEX IF NOT EXISTS idx_priorities_key ON priorities(key);
			CREATE INDEX IF NOT EXISTS idx_priorities_priority ON priorities(priority);
		');
    }