Exposed Maven plugin

The Exposed Maven plugin provides build-time tooling for working with Exposed-based database schemas in Maven projects.

Its primary feature is generating SQL migration scripts by comparing Exposed table definitions with an existing database schema.

Requirements

• Kotlin 2.2 or later
• Maven 3.9 or later
• JVM 11 or later
• Docker (only required when using Testcontainers)

Installation

To install the plugin, add it to the <build><plugins> section of your <path>pom.xml</path> file:

<build>
    <plugins>
        <plugin>
            <groupId>org.jetbrains.exposed.plugin</groupId>
            <artifactId>exposed-maven-plugin</artifactId>
            <version>%exposed_version%</version>
        </plugin>
    </plugins>
</build>

Generate migration scripts

To generate migration scripts based on the difference between your existing database schema and your Exposed table definitions, invoke the generate-migration goal:

mvn exposed:generate-migrations

Generated files are written to the configured output directory.

Integration with the build lifecycle

You can bind migration generation to a Maven lifecycle phase by adding an <executions> block to the plugin configuration. For example, to generate migrations during the process-classes phase:

<plugin>
    <groupId>org.jetbrains.exposed.plugin</groupId>
    <artifactId>exposed-maven-plugin</artifactId>
    <version>%exposed_version%</version>
    <executions>
        <execution>
            <id>generate-migrations</id>
            <phase>process-classes</phase>
            <goals>
                <goal>generate-migrations</goal>
            </goals>
        </execution>
    </executions>
</plugin>

Configuration

Configure the plugin using the <configuration> block inside the plugin entry in your <path>pom.xml</path> file.

At minimum, configure the following parameters:

• tablesPackage as the package name where Exposed table definitions are located.
• A database configuration or a Testcontainers configuration.

Configure a database connection

To configure a database connection, set the databaseUrl, databaseUser, and databasePassword parameters:

<plugin>
    <groupId>org.jetbrains.exposed.plugin</groupId>
    <artifactId>exposed-maven-plugin</artifactId>
    <version>%exposed_version%</version>
    <configuration>
        <tablesPackage>com.example.db.tables</tablesPackage>
        <databaseUrl>jdbc:postgresql://localhost:5432/mydb</databaseUrl>
        <databaseUser>postgres</databaseUser>
        <databasePassword>password</databasePassword>
    </configuration>
</plugin>

Configure Testcontainers {id="testcontainers-config"}

To configure a Testcontainers connection, set the testContainersImageName parameter:

<plugin>
    <groupId>org.jetbrains.exposed.plugin</groupId>
    <artifactId>exposed-maven-plugin</artifactId>
    <version>%exposed_version%</version>
    <configuration>
        <tablesPackage>com.example.db.tables</tablesPackage>
        <testContainersImageName>postgres:latest</testContainersImageName>
    </configuration>
</plugin>

For more details and supported database container images, see .

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When testContainersImageName is configured, the plugin uses Testcontainers instead of a direct database connection for schema generation.

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Override parameters from the command line

To override any plugin parameter on the command line, use the matching exposed.migrations.<name> system property:

mvn exposed:generate-migrations \
    -Dexposed.migrations.tablesPackage=com.example.db.tables \
    -Dexposed.migrations.databaseUrl=jdbc:postgresql://localhost:5432/mydb \
    -Dexposed.migrations.databaseUser=postgres \
    -Dexposed.migrations.databasePassword=password

Additional configuration

Optionally, you can configure the following parameters for additional control over migration generation and file naming:

Directory where migration scripts are stored.

Defaults to src/main/resources/db/migration under the project base directory.

Prefix used for migration script names.

Defaults to "V". </def> <def>

Version format used for migration script names. For supported values, see version formats.

Defaults to a timestamp in the yyyyMMddHHmmss format. </def> <def>

Separator used in migration script names.

Defaults to "__". </def> <def>

Whether the descriptive part of migration script names is converted to uppercase.

Defaults to true. </def> <def>

File extension used for migration scripts.

Defaults to ".sql". </def> </deflist>

Example:

<plugin>
    <groupId>org.jetbrains.exposed.plugin</groupId>
    <artifactId>exposed-maven-plugin</artifactId>
    <version>%exposed_version%</version>
    <configuration>
        <tablesPackage>com.example.db.tables</tablesPackage>
        <databaseUrl>jdbc:postgresql://localhost:5432/mydb</databaseUrl>
        <databaseUser>postgres</databaseUser>
        <databasePassword>password</databasePassword>

        <fileDirectory>${project.basedir}/src/main/resources/db/migration</fileDirectory>
        <filePrefix>V</filePrefix>
        <fileVersionFormat>TIMESTAMP_ONLY</fileVersionFormat>
        <fileSeparator>__</fileSeparator>
        <useUpperCaseDescription>true</useUpperCaseDescription>
        <fileExtension>.sql</fileExtension>
    </configuration>
</plugin>

Version formats

The plugin supports the following fileVersionFormat values:

Example: V20260417195521__CREATE_TABLE_USERS.sql </def> <def>

Example: V202604171955__CREATE_TABLE_USERS.sql </def> <def>

Example: V3_20260417195521__CREATE_TABLE_USERS.sql </def> <def>

Example: V3_202604171955__CREATE_TABLE_USERS.sql </def> <def>

Example: V3_1__CREATE_TABLE_USERS.sql </def> <def>

Example: V3__CREATE_TABLE_USERS.sql </def> </deflist>

For version formats that include a major version, the plugin scans the configured fileDirectory to determine the next available version. If the directory is empty, or if no compatible migration files are found, numbering starts at 1.

File naming

By default, migration scripts use the following naming pattern:

<prefix><version><separator><description><extension>

For example:

V20260417195521__CREATE_TABLE_USERS.sql

The generated description (CREATE_TABLE_USERS) is derived from the generated SQL statement and typically follows this format:

<OPERATION>_<OBJECT>_<IDENTIFIER>_<EXTRA>

When a migration contains multiple SQL statements, the description is usually derived from the first significant statement.

• A migration that creates two related tables typically uses the description of the first CREATE TABLE statement.
• If a sequence must be created before a table, the generated description still prefers the CREATE TABLE statement instead of CREATE SEQUENCE.

If the plugin cannot derive a standard description, it falls back to a generic name, such as CUSTOM_STATEMENT_12345.

Override the generated filename

You can override the generated filename by passing the exposed.migrations.filename system property to the generate-migration goal:

mvn exposed:generate-migrations -Dexpose.migrations.filename=V0__initialize_schema.sql

When exposed.migrations.filename is specified, the plugin generates a single migration script containing all migration statements, even if the schema diff affects multiple tables.

{style="note"}

Using Testcontainers {id="use-testcontainers"}

Testcontainers is a Java library that lets you run temporary Docker containers during tests or build tasks. You can use Testcontainers to start a disposable database instance automatically while generating migration scripts.

Docker must be installed and running to use Testcontainers.

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Testcontainers workflow

When using Testcontainers, the Exposed Maven plugin performs the following steps:

1. Starts a database container.
2. Applies existing migration scripts using Flyway.
3. Compares the resulting database schema with your Exposed table definitions.
4. Generates new migration scripts.
5. Stops the container.

If the configured migration directory contains existing migration scripts, the plugin applies them using Flyway before generating new migrations.

This ensures that newly generated migration scripts are based on the latest schema state, including changes introduced by previous migrations.

Supported databases

The plugin supports the following database container images:

Next steps

The Exposed Maven plugin generates migration scripts, but it does not apply them to your database automatically.

After generating migration scripts, review and apply them using your existing database migration workflow. For example, you can:

• Apply migrations using tools such as Flyway or Liquibase.
• Execute scripts manually using your database client.
• Run scripts from the IntelliJ IDEA Database tool window.
• Integrate migration execution into your CI/CD pipeline.

After applying the generated scripts, your database schema should match your current Exposed table definitions.