GraphQL Server with PostgreSQL and MongoDB

A GraphQL server that supports both PostgreSQL and MongoDB databases, built with Go and gqlgen.

Features

• Dual database support (PostgreSQL and MongoDB)
• GraphQL API with playground
• CRUD operations for Patients
• Database schema validation
• Environment-based configuration

Prerequisites

• Go 1.16 or higher
• PostgreSQL
• MongoDB
• Make (optional, for using Makefile commands)

Setup

1. Clone the repository:

git clone https://github.com/sdshah09/Go-GraphQL
cd my-graphql-server

2. Install dependencies:

go mod download

3. Create a .env file in the root directory:

# PostgreSQL Configuration
DB_HOST=localhost
DB_PORT=5432
DB_USER=postgres
DB_PASSWORD=your_password
DB_NAME=your_db_name

# MongoDB Configuration
MONGO_URI=mongodb://localhost:27017
MONGO_DB=your_db_name

4. Run the server:

go run server.go

The GraphQL playground will be available at http://localhost:8080

API Examples

Create a Patient

mutation {
  createPatient(
    input: {
      first_name: "John"
      last_name: "Doe"
      db: "postgres"  # or "mongo"
    }
  ) {
    id
    first_name
    last_name
  }
}

Query Patients

query {
  patients(db: "postgres") {  # or "mongo"
    id
    first_name
    last_name
  }
}

Database Schemas

PostgreSQL

CREATE TABLE patients (
    id SERIAL PRIMARY KEY,
    first_name VARCHAR(255) NOT NULL,
    last_name VARCHAR(255)
);

MongoDB

{
  $jsonSchema: {
    bsonType: "object",
    required: ["first_name"],
    properties: {
      first_name: {
        bsonType: "string",
        description: "must be a string and is required"
      },
      last_name: {
        bsonType: "string",
        description: "must be a string if present"
      }
    }
  }
}

Project Structure

.
├── config/         # Configuration management
├── graph/          # GraphQL schema and resolvers
├── utils/          # Database utilities
│   ├── postgres/   # PostgreSQL specific code
│   └── mongodb/    # MongoDB specific code
├── server.go       # Main server file
└── .env           # Environment variables

Development

To regenerate GraphQL code after schema changes:

go run github.com/99designs/gqlgen generate