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First Steps: API

Prerequisites

  • Java 6+
  • A working Maven 2 or 3 install

Creating the project

We're going to create our project using the Maven Archetype Plugin by issuing the following command:

> mvn archetype:generate -B ^
        -DarchetypeGroupId=org.apache.maven.archetypes ^
        -DarchetypeArtifactId=maven-archetype-quickstart ^
        -DarchetypeVersion=1.1 ^
        -DgroupId=foo ^
        -DartifactId=bar ^
        -Dversion=1.0-SNAPSHOT ^
        -Dpackage=foobar

We are now ready to get started. Let's jump into our project:

> cd bar

Adding the dependencies

Let's add Flyway and H2 to our new pom.xml:

<project ...>
    ...
    <dependencies>
        <dependency>
            <groupId>org.flywaydb</groupId>
            <artifactId>flyway-core</artifactId>
            <version>4.0.3</version>
        </dependency>
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <version>1.3.170</version>
        </dependency>
        ...
    </dependencies>
    ...
</project>

Integrating Flyway

Now it's time to integrate Flyway into src/main/java/foobar/App.java and point it to our database:

package foobar;

import org.flywaydb.core.Flyway;

public class App {
    public static void main(String[] args) {
        // Create the Flyway instance
        Flyway flyway = new Flyway();

        // Point it to the database
        flyway.setDataSource("jdbc:h2:file:./target/foobar", "sa", null);

        // Start the migration
        flyway.migrate();
    }
}

Creating the first migration

We create the migration directory src/main/resources/db/migration.
Followed by a first migration called src/main/resources/db/migration/V1__Create_person_table.sql:

create table PERSON (
    ID int not null,
    NAME varchar(100) not null
);

Executing our program

It's now time to execute our program by issuing this command:

bar> mvn package exec:java -Dexec.mainClass=foobar.App

If all went well, you should see the following output (timestamps omitted):

INFO: Creating Metadata table: "PUBLIC"."schema_version"
INFO: Current version of schema "PUBLIC": << Empty Schema >>
INFO: Migrating schema "PUBLIC" to version 1 - Create person table
INFO: Successfully applied 1 migration to schema "PUBLIC" (execution time 00:00.062s).

Adding a second migration

If we now add a second migration called src/main/resources/db/migration/V2__Add_people.sql:

insert into PERSON (ID, NAME) values (1, 'Axel');
insert into PERSON (ID, NAME) values (2, 'Mr. Foo');
insert into PERSON (ID, NAME) values (3, 'Ms. Bar');

and execute it by issuing:

bar> mvn package exec:java -Dexec.mainClass=foobar.App

We now get:

INFO: Current version of schema "PUBLIC": 1
INFO: Migrating schema "PUBLIC" to version 2 - Add people
INFO: Successfully applied 1 migration to schema "PUBLIC" (execution time 00:00.090s).

Summary

In this brief tutorial we saw how to

  • integrate Flyway into a project
  • configure it so it can talk to our database
  • write our first couple of migrations

These migrations were then successfully found and executed.

Read the documentation