Generic SQL API Framework

A reusable PHP backend framework for building database APIs using structured JSON requests.

The framework handles request processing, validation, SQL query construction, database execution, and JSON responses.

The current database implementation is focused on Microsoft SQL Server through ODBC.

---

What It Does

Instead of creating separate backend code for every database query, the API accepts a structured JSON request and builds the required query through the backend query layer.

Basic flow:

Client
  |
  | JSON Request
  v
Generic SQL API
  |
  +-- Request Validation
  |
  +-- Query Builder
  |
  +-- Query Execution
  |
  +-- Database Layer
  |
  v
SQL Server

Example request:

{
  "controller": "Query",
  "action": "select",
  "table": "CustomerTable",
  "columns": [
    "Cust_Name",
    "Phone"
  ]
}

The frontend or client only needs to send the request. The backend handles the SQL generation and execution.

---

Current Features

API

• JSON-based requests
• Controller/action handling
• JSON responses
• Request validation
• CORS handling
• Error handling

Query Engine

• SELECT queries
• WHERE conditions
• JOINs
• GROUP BY
• HAVING
• ORDER BY
• Pagination
• Column aliases
• Table aliases
• SQL expressions
• SQL functions
• Prepared query execution
• Multiple-result execution
• SQL file execution
• Query execution statistics

Database

• Microsoft SQL Server
• ODBC connectivity
• SQL Server authentication
• Windows authentication
• Automatic ODBC driver selection
• Specific ODBC driver selection
• Database metadata access
• Database connection validation

Runtime

Windows includes a prebuilt PHP runtime.

runtime/
└── windows/
    └── php/

Therefore, a Windows deployment does not require a separate PHP installation when using the bundled runtime.

---

Windows Quick Start

1. Configure the Database

Create:

database/config/database.json

Example:

{
  "provider": "sqlserver",
  "driver": "auto",
  "server": "localhost\\SQLEXPRESS",
  "database": "TestDB",
  "authentication": "windows",
  "port": 1433,
  "options": {
    "encrypt": false,
    "trustServerCertificate": true
  }
}

See:

Database Configuration

---

2. Start the API

Run from the project root:

start-windows.bat

The startup script automatically checks:

PHP Runtime
PHP Configuration
Runtime Directories
PHP ODBC
Database Configuration
Database Connection
API Directory
Available Port

Required runtime directories are also created automatically.

---

3. API Starts

The default port starts from:

8000

If the port is already being used, the script automatically searches for another available port up to:

8100

The selected API URL is printed in the console.

Example:

========================================
              API Ready
========================================

API: http://localhost:8000

---

Windows Runtime

The bundled runtime is intended to make Windows deployment simpler.

You do not need to install:

PHP
XAMPP
WAMP

just to run the API with the bundled runtime.

The project can still be hosted using an existing PHP environment such as:

Apache
IIS
Nginx
XAMPP

when required by the deployment.

The bundled runtime is currently provided for Windows.

Linux runtime packaging is planned for a future release.

See:

Hosting

---

Database Connectivity

The current database connection flow is:

Generic SQL API
      |
      v
PHP ODBC Extension
      |
      v
SQL Server ODBC Driver
      |
      v
Microsoft SQL Server

The API does not depend on only one fixed SQL Server ODBC driver version.

The configuration can use:

"driver": "auto"

or specify an installed driver explicitly.

For example:

"driver": "ODBC Driver 18 for SQL Server"

The required ODBC driver must be installed on the host system.

See:

Database Configuration

---

Database Startup Check

The Windows launcher verifies the database connection before starting the API.

Successful:

Checking database connection...

[OK] Database Connected

Failed:

[FAILED] Database connection failed.

If the connection fails, the API startup is aborted.

The database configuration file is:

database/config/database.json

---

API Example

A basic request:

POST /api/index.php
Content-Type: application/json

{
  "controller": "Query",
  "action": "select",
  "table": "CustomerTable",
  "columns": [
    "Cust_Name",
    "Phone"
  ]
}

The API returns JSON containing the result.

Example:

{
  "success": true,
  "data": [
    {
      "Cust_Name": "ABC Traders",
      "Phone": "9876543210"
    }
  ]
}

See:

API Reference

---

Query Example

Filtering:

{
  "controller": "Query",
  "action": "select",
  "table": "CustomerTable",
  "columns": [
    "Cust_Name",
    "City"
  ],
  "where": [
    {
      "left": {
        "column": "City"
      },
      "operator": "=",
      "right": "Bangalore"
    }
  ]
}

For more examples:

Query Examples

For the complete JSON request structure:

JSON Request Reference

---

Project Structure

The main project areas are:

Generic SQL API
│
├── api/
│   └── index.php
│
├── database/
│   └── config/
│       └── database.json
│
├── docs/
│
├── runtime/
│   └── windows/
│       └── php/
│
├── scripts/
│
├── logs/
│
├── start-windows.bat
│
├── CONTRIBUTING.md
├── CHANGELOG.md
└── README.md

Generated and local files such as database credentials, logs, and runtime cache should not be committed.

---

Architecture

The backend is separated into layers:

HTTP/API
   |
   v
Controller
   |
   v
Validation
   |
   v
Query Repository
   |
   v
Query Builder
   |
   v
Query Engine
   |
   v
Database Layer
   |
   v
ODBC
   |
   v
SQL Server

More details:

Architecture

---

Documentation

Document	Purpose
Introduction	Project overview and scope
Architecture	Backend structure and internal flow
API	HTTP API usage
JSON Request Reference	JSON request fields and structure
Query Examples	Practical API requests
Database Configuration	SQL Server and ODBC configuration
Hosting	Running and deploying the backend
Roadmap	Planned backend features
Contributing	Development and contribution guidelines
Changelog	Version history

---

Security

Do not commit production database credentials.

Keep:

database/config/database.json

out of Git when it contains real credentials.

For production deployments:

• Use HTTPS.
• Restrict CORS origins.
• Protect database credentials.
• Do not expose SQL Server directly to the Internet.
• Use appropriate authentication.
• Keep PHP and ODBC components updated.
• Monitor application logs.
• Maintain database backups.

---

Project Scope

This repository is focused on the backend database API.

Included

• Backend API
• JSON request processing
• SQL query generation
• Query execution
• Database connectivity
• Database validation
• Database metadata
• ODBC integration
• Logging
• Query statistics
• Runtime/deployment support

Not Included

This repository does not provide:

• Frontend UI
• Dashboards
• Charts
• Reporting screens
• Frontend routing
• Frontend state management
• Website design

These are handled by applications that consume the API.

---

Roadmap

Planned backend work includes:

CRUD
  |
  v
Transactions
  |
  v
Advanced SQL
  |
  v
Database Metadata
  |
  v
API Security
  |
  v
Performance
  |
  v
Additional Database Providers
  |
  v
Linux / Deployment Improvements

See:

Roadmap

---

Contributing

Contributions are welcome.

Before making changes, read:

Contributing Guide

Keep backend layers separated and update the relevant documentation when changing the API contract.

---

Changelog

See:

CHANGELOG.md

---

License

This project is licensed under the MIT License.

See the LICENSE file for details.