Using Flyway to Manage PostgreSQL Migrations in a Java Project

### Step 1: Set Up Your Java Project 1. **Create a new Java project** (using your preferred IDE like IntelliJ IDEA or Eclipse). 2. **Add Maven or Gradle as your build tool.** If you are using Maven, create a `pom.xml` file. For Gradle, create a `build.gradle` file. ### Step 2: Include Flyway Dependency - **For Maven:** Add the following dependency in your `pom.xml`: ```xml <dependency> <groupId>org.flywaydb</groupId> <artifactId>flyway-core</artifactId> <version>9.16.0</version> </dependency> ``` - **For Gradle:** Add the following line in your `build.gradle`: ```groovy implementation 'org.flywaydb:flyway-core:9.16.0' ``` ### Step 3: Configure Flyway 1. **Create a configuration file (application.properties or application.yml)** in the `src/main/resources` directory. 2. **Add the following properties for PostgreSQL:** ```properties flyway.url=jdbc:postgresql://localhost:5432/your_database_name flyway.user=your_username flyway.password=your_password ``` ### Step 4: Create a Migration Script 1. **Create a directory for migrations:** Create a folder named `db/migration` under `src/main/resources`. 2. **Add a SQL migration file:** Create a file named `V1__Create_table.sql` in the `db/migration` directory with the following content: ```sql CREATE TABLE users ( id SERIAL PRIMARY KEY, username VARCHAR(50) NOT NULL, password VARCHAR(50) NOT NULL ); ``` ### Step 5: Run Flyway Migrations 1. **Create a main Java class (e.g., `Application.java`):** ```java import org.flywaydb.core.Flyway; public class Application { public static void main(String[] args) { Flyway flyway = Flyway.configure().load(); flyway.migrate(); System.out.println("Database migration completed successfully!"); } } ``` 2. **Run your application:** This will apply the migration to your PostgreSQL database. ### Step 6: Verify the Migration - Use a PostgreSQL client or tool (like pgAdmin) to connect to your database and verify that the `users` table has been created successfully. ### Additional Notes - Make sure your PostgreSQL server is running. - Adjust the database URL, username, and password in your configuration to match your PostgreSQL setup. - Always back up your database before running migrations in a production environment. ### Resources - [Flyway Documentation](https://flywaydb.org/documentation/) - [PostgreSQL Documentation](https://www.postgresql.org/docs/)