Limbas

Limbas is a low‑code database framework that turns relational data into fully functional web applications with minimal hand‑coded logic. At its core, it exposes a graphical interface for designing tables, relationships, forms, reports and workflows while generating the underlying PHP code automatically. The system is built to be database agnostic – it supports PostgreSQL, MySQL, MSSQL, SAP MaxDB and Oracle via PDO/UnixODBC, allowing developers to target the same application logic across multiple environments.

Architecture

• Language & Runtime: PHP 8+ is the primary execution layer, leveraging modern language features (typed properties, arrow functions) for maintainability.
• Web Server: Apache is the recommended HTTP server; the framework expects an Apache module setup (mod_php or PHP-FPM) and standard .htaccess rewrites to route all requests through public/index.php.
• Database Connectivity: Uses PDO for database abstraction, with an optional UnixODBC bridge for legacy drivers (e.g., SAP MaxDB). The ORM‑like layer is lightweight and auto‑generates SQL based on the schema defined in the GUI.
• Front‑end: The UI is rendered with server‑side templates (likely PHP/HTML) and enriched by JavaScript for drag‑and‑drop editing. No heavy SPA frameworks are required, keeping the bundle size small and easing integration into existing PHP stacks.
• Containerization: A Docker image (limbas/limbas) is maintained, exposing the public directory as the web root. The image runs a pre‑configured Apache/PHP environment, making deployment on Kubernetes or Docker Compose trivial.

Core Capabilities

• Visual Database Design: Drag‑and‑drop table and field creation, relationship mapping, and constraint enforcement—all stored in the target database’s metadata tables.
• Form & Report Builder: GUI editors generate CRUD interfaces and PDF/HTML reports, with support for custom templates via Smarty or similar templating engines.
• Workflow Engine: Basic state machines and event hooks allow developers to define approval chains or automated actions without writing procedural code.
• API Exposure: While not a REST framework per se, Limbas exposes service endpoints (e.g., /api/records) that can be consumed by external applications. Custom PHP modules can register new endpoints or extend existing ones.
• Plugin Architecture: The plugins directory hosts modular extensions; developers can ship PHP classes that hook into lifecycle events (e.g., onRecordCreate). This mechanism enables integration with external services such as LDAP, OAuth, or third‑party SaaS APIs.

Deployment & Infrastructure

• Self‑Hosting Requirements: A Linux server with Apache, PHP 8+, and a supported RDBMS. The minimal footprint (≈200 MB Docker image) allows deployment on shared hosts or cloud VMs.
• Scalability: The stateless PHP process model scales horizontally by adding more Apache/PHP workers or deploying multiple container replicas behind a load balancer. Database sharding is not built‑in but can be achieved by pointing different Limbas instances to separate database shards.
• Backup & Upgrade: The upgrade process is file‑based (replace limbas_src, vendor, and assets). Version control of the application code is recommended to track changes across deployments.

Integration & Extensibility

• Webhooks: Custom PHP scripts can emit HTTP callbacks after CRUD events, enabling real‑time synchronization with external systems.
• Scripting: Developers can embed PHP scripts directly in forms or reports, granting fine‑grained control over business logic.
• RESTful Bridges: By exposing Limbas endpoints behind an API gateway, developers can expose the application as a microservice and integrate with modern JavaScript front‑ends or mobile apps.
• Customization: Theme files, CSS overrides, and JavaScript plugins can be added to the public/assets directory, allowing UI tailoring without touching core code.

Developer Experience

• Documentation: The official site hosts a comprehensive guide, including a “Get Started” tutorial and API references. Community forums on SourceForge provide peer support.
• Community & Licensing: LGPL‑style GPL 2.0 licensing ensures freedom to modify and redistribute, while the open‑source nature encourages community plugins.
• Learning Curve: The low‑code paradigm reduces the need for boilerplate code, but developers still benefit from understanding PHP and SQL to extend or debug generated logic.

Use Cases

Advantages Over Alternatives

• Zero‑Code Boilerplate: Eliminates repetitive CRUD scaffolding, accelerating MVP delivery.
• Database Agnostic: One codebase runs on PostgreSQL, MySQL, MSSQL, SAP MaxDB or Oracle.
• PHP Native: Fits naturally into existing PHP ecosystems; no need for separate backend frameworks.
• Open Source & Extensible: GPL 2.0 licensing and a plugin system allow deep customization without vendor lock‑in