🏢 Go Pegawai - Employee Management System

A comprehensive employee management application built with Go and GORM, demonstrating full CRUD operations with MariaDB database integration, environment-based configuration, and enterprise-grade best practices.

📋 Table of Contents

Features
Tech Stack
Prerequisites
Installation
Usage
Project Structure
Database Schema
API Documentation
Examples
Contributing
License

✨ Features

Complete CRUD Operations: Create, Read, Update, and Delete employee records
MariaDB Integration: Production-ready MariaDB database with GORM ORM
Environment Configuration: Secure configuration management with environment variables
Connection Pooling: Optimized database connections for performance
Annual Salary Calculation: Automatic calculation of yearly salary (12 × monthly salary)
Data Persistence: MariaDB database for reliable, scalable data storage
Soft Deletes: Safe deletion with GORM's built-in soft delete functionality
Clean Architecture: Organized code structure with separate packages
Error Handling: Comprehensive error handling for all operations
Security Best Practices: Environment variables for sensitive data
Console Interface: User-friendly console output with formatted display

🛠 Tech Stack

Language: Go 1.21+
ORM: GORM v1.31.0
Database: MariaDB/MySQL
Database Driver: MySQL Driver v1.8.1
Configuration: godotenv v1.5.1 for environment variable management

📋 Prerequisites

Before running this application, make sure you have the following installed:

Go (version 1.21 or later)
MariaDB or MySQL (version 8.0 or later)
Git (for cloning the repository)

🚀 Installation

Clone the repository

git clone https://github.com/muslchn/go-pegawai.git
cd go-pegawai

Install dependencies
```
go mod tidy
```

Set up MariaDB database

-- Connect to MariaDB as root
mysql -u root -p

-- Create database
CREATE DATABASE pegawai_db CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

-- Create user (optional, for security)
CREATE USER 'pegawai_user'@'localhost' IDENTIFIED BY 'your_secure_password';
GRANT ALL PRIVILEGES ON pegawai_db.* TO 'pegawai_user'@'localhost';
FLUSH PRIVILEGES;

Configure environment variables

Copy the example environment file and update with your database credentials:

cp .env.example .env

Edit .env file with your database configuration:

# Database Configuration
DB_HOST=localhost
DB_PORT=3306
DB_USERNAME=root
DB_PASSWORD=your_password
DB_NAME=pegawai_db

# Application Configuration
APP_PORT=8080
APP_ENV=development

# Database Connection Settings
DB_MAX_OPEN_CONNS=25
DB_MAX_IDLE_CONNS=10
DB_CONN_MAX_LIFETIME=300

Run the application
```
go run main.go
```

💻 Usage

The application runs a demonstration of all CRUD operations automatically:

go run main.go

Application Flow

Configuration Loading: Loads environment variables from .env file
Database Initialization: Connects to MariaDB and migrates schema
CREATE: Adds 5 sample employees to the database
READ: Displays all employees with salary calculations
UPDATE: Modifies an employee's salary and shows the changes
DELETE: Removes an employee and displays updated list
SUMMARY: Shows final employee list with statistics

📁 Project Structure

go-pegawai/
├── main.go                 # Main application entry point
├── go.mod                  # Go module definition
├── go.sum                  # Go module checksums
├── .env                    # Environment variables (not in git)
├── .env.example            # Environment variables template
├── .gitignore              # Git ignore file
├── config/                 # Configuration package
│   └── config.go           # Environment variable loading and config management
├── pegawai/                # Employee package
│   └── data.go             # Employee struct and CRUD operations
└── README.md               # Project documentation

🗄 Database Schema

Pegawai Table (MariaDB)

Column	Type	Constraints	Description
id	BIGINT	PRIMARY KEY, AUTO_INC	Unique employee identifier
created_at	DATETIME(3)	NOT NULL	Record creation timestamp
updated_at	DATETIME(3)	NOT NULL	Record last update timestamp
deleted_at	DATETIME(3)	NULL	Soft delete timestamp
nama	VARCHAR(100)	NOT NULL	Employee full name
posisi	VARCHAR(100)	NOT NULL	Employee position/role
gaji_bulanan	DECIMAL(15,2)	NOT NULL	Monthly salary amount

Database Configuration

Character Set: utf8mb4
Collation: utf8mb4_unicode_ci
Engine: InnoDB (default)
Connection Pool: Configurable via environment variables

📚 API Documentation

Core Functions

Database Operations

// Initialize database connection
func InitDatabase() error

// Create new employee
func CreatePegawai(pegawai *Pegawai) error

// Get all employees
func GetAllPegawai() ([]Pegawai, error)

// Get employee by ID
func GetPegawaiByID(id uint) (*Pegawai, error)

// Update employee salary
func UpdatePegawaiSalary(id uint, newSalary float64) error

// Delete employee (soft delete)
func DeletePegawai(id uint) error

// Display all employees with formatting
func DisplayAllPegawai() error

Configuration Management

// Load configuration from environment variables
func LoadConfig() (*Config, error)

// Get current configuration instance
func GetConfig() *Config

// Configuration structures
type Config struct {
    Database DatabaseConfig
    App      AppConfig
}

type DatabaseConfig struct {
    Host            string
    Port            int
    Username        string
    Password        string
    Name            string
    MaxOpenConns    int
    MaxIdleConns    int
    ConnMaxLifetime int
}

type AppConfig struct {
    Port string
    Env  string
}

Employee Methods

// Calculate annual salary
func (p Pegawai) HitungGajiTahunan() float64

// Display employee information
func (p Pegawai) TampilkanInformasi()

Data Structures

type Pegawai struct {
    gorm.Model           // ID, CreatedAt, UpdatedAt, DeletedAt
    Nama        string   `gorm:"size:100;not null" json:"nama"`
    Posisi      string   `gorm:"size:100;not null" json:"posisi"`
    GajiBulanan float64  `gorm:"not null" json:"gaji_bulanan"`
}

📖 Examples

Sample Output

🏢 APLIKASI MANAJEMEN DATA PEGAWAI 🏢
=====================================

🔧 DEMO OPERASI CRUD PEGAWAI
============================

📝 STEP 1: MENAMBAH 5 DATA PEGAWAI
----------------------------------
✅ Pegawai berhasil ditambahkan dengan ID: 1
✅ Pegawai berhasil ditambahkan dengan ID: 2
...

📊 STEP 2: MENAMPILKAN SEMUA DATA PEGAWAI
------------------------------------------
MariaDB database connected successfully to localhost:3306/pegawai_db
Database schema migrated successfully

👤 PEGAWAI 1:
=== INFORMASI PEGAWAI ===
ID: 1
Nama: Ahmad Wijaya
Posisi: Software Engineer
Gaji Bulanan: Rp 8,500,000.00
Gaji Tahunan: Rp 102,000,000.00
========================

Sample Employee Data

ID	Name	Position	Monthly Salary	Annual Salary
1	Ahmad Wijaya	Software Engineer	Rp 8,500,000	Rp 102,000,000
2	Siti Nurhaliza	Product Manager	Rp 12,000,000	Rp 144,000,000
3	Budi Santoso	UI/UX Designer	Rp 7,500,000	Rp 90,000,000
4	Rina Marlina	Data Analyst	Rp 9,000,000	Rp 108,000,000
5	Doni Prasetyo	DevOps Engineer	Rp 10,500,000	Rp 126,000,000

🔍 Key Features Demonstrated

CRUD Operations

✅ Create: Insert 5 employees with complete information
✅ Read: Retrieve and display all employee data
✅ Update: Modify employee salary with before/after comparison
✅ Delete: Remove employee record with confirmation

Business Logic

✅ Annual Salary Calculation: 12 × monthly salary
✅ Data Validation: GORM constraints and error handling
✅ Soft Deletes: Safe record removal
✅ Statistics: Total and average salary calculations

🛡 Error Handling

The application includes comprehensive error handling for:

Database connection failures
Environment variable loading errors
Record not found scenarios
Invalid data constraints
SQL operation errors
Configuration validation errors

🔧 Configuration

Environment Variables

The application uses environment variables for configuration. Copy .env.example to .env and configure:

# Database Configuration
DB_HOST=localhost                # Database host
DB_PORT=3306                     # Database port
DB_USERNAME=root                 # Database username
DB_PASSWORD=your_password        # Database password
DB_NAME=pegawai_db              # Database name

# Application Configuration
APP_PORT=8080                    # Application port
APP_ENV=development              # Environment (development/production)

# Database Connection Settings
DB_MAX_OPEN_CONNS=25            # Maximum open connections
DB_MAX_IDLE_CONNS=10            # Maximum idle connections
DB_CONN_MAX_LIFETIME=300        # Connection lifetime in seconds

Security Best Practices

✅ Environment variables for sensitive data
✅ .env file excluded from version control
✅ .env.example template for setup
✅ Database connection pooling
✅ Proper error handling without exposing internals

🧪 Testing

To run the application and see all operations:

# Ensure MariaDB is running
sudo systemctl start mariadb  # or: brew services start mariadb

# Create database
mysql -u root -p -e "CREATE DATABASE IF NOT EXISTS pegawai_db;"

# Run the main demo
go run main.go

# Check database tables (optional)
mysql -u root -p pegawai_db -e "SHOW TABLES; DESCRIBE pegawais;"

Development Commands

# Build the application
go build

# Run with specific environment
APP_ENV=production go run main.go

# Check dependencies
go mod tidy
go mod verify

# Format code
go fmt ./...

🤝 Contributing

Fork the repository
Create your feature branch (git checkout -b feature/AmazingFeature)
Commit your changes (git commit -m 'Add some AmazingFeature')
Push to the branch (git push origin feature/AmazingFeature)
Open a Pull Request

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

📞 Contact

Author: muslchn
Repository: go-pegawai

🙏 Acknowledgments

GORM - The fantastic ORM library for Go
MariaDB - Reliable and scalable database
godotenv - Environment variable management
Go community for excellent documentation and support

Note: This application demonstrates Go programming concepts, GORM usage, MariaDB integration, and enterprise-grade configuration management. The application includes production-ready features like connection pooling, environment-based configuration, and comprehensive error handling.

muslchn/go-pegawai