LibreOffice - Base - Base, database, database frontend, LibreOffice, ODF, Open Standards, SQL, ODBC
Kodiak PHP - Kodiak PHP can run any PHP code directly (offline) on your iPad, no need for an internet connection.
My Visual Database - Using My Visual Database, you can create databases for invoicing, inventory, CRM, or any specific purpose.
CodeLobster PHP Edition - CodeLobster - Free portable PHP IDE with support Drupal, Smarty, Twig, WordPress, Joomla, JQuery, CodeIgniter, HTML, CSS, JavaScript, AngularJS, CakePHP, Facebook, Laravel, Phalcon, Symfony, Yii
MongoDB - MongoDB (from "humongous") is a scalable, high-performance NoSQL database.
Nova - Nova is an all-in-one productivity tool. With Nova you can freely choose which components to add to your projects and which you need for productivity, without any pre-set template.