<?php

use Appwrite\Client;
use Appwrite\Services\Databases;

$client = (new Client())
    ->setEndpoint('https://cloud.appwrite.io/v1') // Your API Endpoint
    ->setProject('<YOUR_PROJECT_ID>') // Your project ID
    ->setKey('<YOUR_API_KEY>'); // Your secret API key

$databases = new Databases($client);

$result = $databases->delete(
    databaseId: '<DATABASE_ID>'
);