Micronaut, a powerful and lightweight framework, provides an excellent platform for building microservices. In this blog, we’ll explore the seamless integration of MySQL, a popular relational database, into a Micronaut application. This integration ensures data persistence with efficiency and simplicity.

Prerequisites

Before connecting to a database in Micronaut, make sure you have the following prerequisites:

1. Micronaut Application: Create a Micronaut project or have an existing one.
2. Database: Ensure that you have a running instance of your chosen database system (e.g., MySQL) with a database schema and credentials.
3. Docker: Required only if you don’t have MySql instance running.

Steps to Connect to a SQL Database in Micronaut

1. Run MySQL Database

If you already have an instance running you can skip this step. We will use docker to run a MySQL Container on port 3306 with root password as “root”

docker run -d -p 3306:3306 --name mysql-docker-container -e MYSQL_ROOT_PASSWORD=sqlPassword -e MYSQL_DATABASE=my_sql -e MYSQL_USER=sqlUser -e MYSQL_PASSWORD=sqlPassword mysql/mysql-server:lates

2. Add Database Driver Dependencies

Open your project in your favorite IDE, and navigate to the build.gradle file. Add the MySQL connector dependency to the dependencies block:

dependencies {
    // ...
    implementation('io.micronaut.sql:micronaut-jdbc-hikari:4.3.0')
    implementation("io.micronaut.data:micronaut-data-jdbc")
    runtimeOnly("mysql:mysql-connector-java")
}

3. Configure Database Connection

Micronaut allows you to configure the database connection in the application.yml (or application.properties) file. Specify the database URL, username, and password as follows:

datasources:
  default:
    url: jdbc:mysql://localhost:3306/my_sql?preparedStatementCacheQueries=0
    driverClassName: com.mysql.cj.jdbc.Driver
    username: sqlUser
    password: sqlPassword
    dialect: MYSQL

4. Create Model, Controller and Repository

Refer for these details: How to Connect Postgres in Micronaut

5. Check if it’s working

curl --location 'http://localhost:8080/student/' \
--header 'Content-Type: application/json' \
--data '{
    "name": "Bhanu"
}'

PR for reference: https://github.com/cw-bhanunadar/Micronaut-playground/pull/17