This brief tutorial will teach how to get up and running with the MigrateDB API. It will take you through the steps on how to configure it and how to write and execute your first few database migrations.
This tutorial should take you about 5 minutes to complete.
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
Let’s add MigrateDB and H2 to our new pom.xml
:
<project xmlns="...">;
...
<dependencies>
<dependency>
<groupId>de.unentscheidbar</groupId>
<artifactId>migratedb-core</artifactId>
<version>1.0.0</version>
</dependency>
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<version>2.1.212</version>
</dependency>
...
</dependencies>
<plugins>
<plugin>
<groupId>de.unentscheidbar</groupId>
<artifactId>migratedb-maven-plugin</artifactId>
<version>1.0.0</version>
<executions>
<execution>
<goals>
<goal>scan</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
...
</project>
Now it’s time to integrate MigrateDB into src/main/java/foobar/App.java
and point it to our database:
package foobar;
import migratedb.1.core.MigrateDB;
public class App {
public static void main(String[] args) {
// Create the MigrateDB instance and point it to the database
var migratedb = MigrateDb.configure().dataSource("jdbc:h2:file:./target/foobar", "sa", null).load();
// Start the migration
migratedb.migrate();
}
}
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
);
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 schema history table: "PUBLIC"."migratedb_state" 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).
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).
In this brief tutorial we saw how to
These migrations were then successfully found and executed.