MYBATIS Migrations

Migration Gradle plugin is a Gradle plugin that integrates into the Gradle life cycle, the MyBatis 3 Migration tool. MyBatis 3 Migration Schema is a tool that helps you to manage database schema changes.

Getting Started

First off, make sure your project uses Java 11 or higher, as this is required. After that, we need to apply the plugin to your project. The way we do this is with the plugins block:

plugins {
    id 'com.github.boginw.mybatis-migrations' version '0.4.0'
}

After applying the plugin, all the same functionality of the MyBatis Migrations CLI tool are now available by using Gradle Tasks.

Configuration

You might already have a setup going, or you want something custom. In this case, the plugin provides a configuration block named migrations, which you can use to change the defaults of the tasks. The plugin allows configuring:

• baseDir: The base directory for which tasks are run. Default is migrations.
• environment: Which environment the tasks will use. See MyBatis' documentation. Default is development
• force: Whether to force script to continue even if SQL errors or warnings are encountered. Default is false.

An example of such a block is shown below:

migrations {
    baseDir = new File('migrations')
    environment = "development"
    force = false
}

It is possible to override the configured environment by providing a new environment with the --env option, i.e. --env production.

Database Drivers and Hook Languages

The plugin removes the requirement of downloading jars and adding them to folders. Instead, the plugin loads all the project's dependencies from the main source set and passes them to MyBatis. The plugin also creates a configuration scope with the name migrationsRuntime, which you can use to register database drivers and hook languages (JSR-223). In the following the driver for H2 is registered, along with dependencies for the Groovy language for hooks:

dependencies {
    migrationsRuntime 'com.h2database:h2:1.4.200'
    implementation 'org.codehaus.groovy:groovy:3.0.9'
    migrationsRuntime 'org.codehaus.groovy:groovy-jsr223:3.0.9'
}

Tasks

The plugin enables the same commands as available in the MyBatis Migrations CLI tool through Gradle. All tasks are prefixed with migrate followed by the command name with the initial letter of the command capitalized, i.e., migrateInit, for init. Gradle requires giving names to arguments; therefore, the arguments are not the same between the CLI tool and this plugin. Below is a list of commands and their arguments.

All commands have an output option. This option specifies where the output from commands should be printed to. You can set this option by specifying --output <FILE-PATH> where <FILE-PATH> is a path to a file where the output should be forwarded to.

• migrateInit: Initializes a new 'migration path', also called a ' repository' (of migration scripts)
  • --idPattern: Change the default timestamp based file prefix to number sequence
• migrateBootstrap: Use the current state of the database schema as the starting point
• migrateNew: Generates the skeleton of a migration script that you can then simply fill in
  • --name: The name of the migration
• migrateStatus: Report the current state of the database
• migrateUp: Runs the do section of all pending migrations in order, one after the other
  • --steps: The number of migrations that should be applied
• migrateDown: Runs the undo section of the last applied migration only
  • --steps: The number of migrations that should be undone
• migrateRedo: Is a shortcut for executing a down command and up command
  • --steps: The number of migrations to redo. The default is 1.
• migrateVersion: Migrate the schema to any specific version of the database you like
  • --version: The version you like to migrate to
• migratePending: Runs all pending migrations regardless of their order or position in the status log
• migrateScript: Generate a script that can migrate a schema from one version to another
  • --from: The version to migrate from
  • --to: The version to migrate to