Examples

Explore real-world examples of using Kapper in various scenarios. All examples include complete, runnable code that you can use as a starting point for your own projects.

Quick Navigation

Kotlin Examples

• Basic CRUD Operations
• Advanced Queries
• Transaction Handling
• Coroutines & Flow

Java Examples

• Basic CRUD with Records
• Java Records Support

Framework Comparisons

• Kapper vs Hibernate
• Kapper vs Ktorm

Database Schema

All examples use a superhero-themed database schema:

CREATE TABLE super_heroes (
    id UUID PRIMARY KEY,
    name VARCHAR(255) NOT NULL,
    email VARCHAR(255),
    age INT
);

CREATE TABLE villains (
    id UUID PRIMARY KEY,
    name VARCHAR(255) NOT NULL
);

CREATE TABLE battles (
    super_hero_id UUID REFERENCES super_heroes(id),
    villain_id UUID REFERENCES villains(id),
    battle_date TIMESTAMP NOT NULL,
    updated_ts TIMESTAMP NOT NULL,
    PRIMARY KEY (super_hero_id, villain_id, battle_date)
);

Database setup scripts are available for:

• PostgreSQL
• MySQL

Project Structure

The complete examples are available in the examples directory of the main repository:

examples/
├── kotlin-example/          # Kotlin examples and tests
├── java-example/           # Java examples and tests
├── db/                     # Database setup scripts
└── docs/                   # Blog posts and additional documentation

Running the Examples

1. Clone the repository:

   git clone https://github.com/driessamyn/kapper.git
   cd kapper/examples

2. Set up your database using the scripts in /db

3. Run the examples:

   # Kotlin examples
   ./gradlew :kotlin-example:test
   
   # Java examples  
   ./gradlew :java-example:test

Key Concepts Demonstrated

• Auto-mapping: How Kapper automatically maps SQL results to Kotlin data classes and Java records
• Parameter binding: Different ways to pass parameters to SQL queries
• Transaction handling: Managing database transactions effectively
• Error handling: Proper exception handling and resource management
• Performance patterns: Writing efficient queries and bulk operations
• Database compatibility: Working with different database engines

Ready to dive in? Start with Basic CRUD Operations or jump to any specific example that interests you.