Kotlin: Database Migration – Harmonica 1.0.1

Table of Contents

Here, I announce the new release of Kotlin db migration library, Harmonica 1.0.1.

You can see the code in GitHub.

New Feature

Execute migration after compilation

Before, it reads migration script as Kotlin script and execute it. This time, I added new Gradle tasks, jarmonicaCreate, jarmonicaUp, jarmonicaDown. Those tasks compile Kotlin code as an application, first, and execute the migration.

In new tasks, db connection is handled better than before commands.

Of course you can use old commands, harmonicaUp, harmonicaDown, harmonicaCreate.

How to use

build.gradle

To use new commands, build.gradle must be changed than before.

buildscript {
ext.kotlin_version = '1.2.41'
repositories {
jcenter()
mavenCentral()
maven { url 'https://jitpack.io' } // required
}
dependencies {
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
classpath 'com.github.KenjiOhtsuka:harmonica:1.0.1' // required
}
}
group 'yourgroup'
version 'yourversion'
apply plugin: 'kotlin'
apply plugin: 'jarmonica' // enable new commands
// specify the directory to put migration classes
extensions.extraProperties["directoryPath"] = "src/main/kotlin/db"
// specify the package the migration classes have.
extensions.extraProperties["migrationPackage"] = "db"
sourceCompatibility = 1.8
repositories {
mavenCentral()
maven { url 'https://jitpack.io' } // required
maven {
url  "https://dl.bintray.com/kotlin/exposed" // required
}
}
dependencies {
compile 'org.jetbrains.exposed:exposed:0.10.2' // if you use Exposed
compile "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
compile group: 'org.reflections', name: 'reflections', version: '0.9.11' // required
compile files('/lib/postgresql-42.2.2.jar') // JDBC driver
compile 'com.github.KenjiOhtsuka:harmonica:1.0.1' // required
/* required */
compile group: 'org.jetbrains.kotlin', name: 'kotlin-script-runtime', version: kotlin_version
compile group: 'org.jetbrains.kotlin', name: 'kotlin-script-util', version: kotlin_version
compile group: 'org.jetbrains.kotlin', name: 'kotlin-reflect', version: kotlin_version
}
compileKotlin {
kotlinOptions { jvmTarget = "1.8" }
}
compileTestKotlin {
kotlinOptions { jvmTarget = "1.8" }
}

buildscript {

ext.kotlin_version = '1.2.41'

repositories {

jcenter()

mavenCentral()

maven { url 'https://jitpack.io' } // required

}

dependencies {

classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"

classpath 'com.github.KenjiOhtsuka:harmonica:1.0.1' // required

}

group 'yourgroup'

version 'yourversion'

apply plugin: 'kotlin'

apply plugin: 'jarmonica' // enable new commands

// specify the directory to put migration classes

extensions.extraProperties["directoryPath"] = "src/main/kotlin/db"

// specify the package the migration classes have.

extensions.extraProperties["migrationPackage"] = "db"

sourceCompatibility = 1.8

repositories {

mavenCentral()

maven { url 'https://jitpack.io' } // required

maven {

url "https://dl.bintray.com/kotlin/exposed" // required

}

dependencies {

compile 'org.jetbrains.exposed:exposed:0.10.2' // if you use Exposed

compile "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"

compile group: 'org.reflections', name: 'reflections', version: '0.9.11' // required

compile files('/lib/postgresql-42.2.2.jar') // JDBC driver

compile 'com.github.KenjiOhtsuka:harmonica:1.0.1' // required

/* required */

compile group: 'org.jetbrains.kotlin', name: 'kotlin-script-runtime', version: kotlin_version

compile group: 'org.jetbrains.kotlin', name: 'kotlin-script-util', version: kotlin_version

compile group: 'org.jetbrains.kotlin', name: 'kotlin-reflect', version: kotlin_version

}

compileKotlin {

kotlinOptions { jvmTarget = "1.8" }

}

compileTestKotlin {

kotlinOptions { jvmTarget = "1.8" }

}

Plugin preparation: Add dependency in build script dependency and apply the plugin jarmonica
Dependency for compilation: Add some library to dependencies for compilation. If you want to use Exposed, add it, too.

Directory Structure

Set up directory structure. This part is the same as before.

`- src
`- main
`- kotlin
`- db
|- config
| `- Default.kt <- default configuration file
`- migration

`- src

`- main

`- kotlin

`- db

|- config

| `- Default.kt <- default configuration file

`- migration

Database Configuration

Put the class Default.

package db.config
import com.improve_future.harmonica.core.DbConfig
import com.improve_future.harmonica.core.Dbms
class Default: DbConfig({
dbms = Dbms.PostgreSQL
user = "developer"
password = "developer"
host = "127.0.0.1"
dbName = "harmonica_test"
})

package db.config

import com.improve_future.harmonica.core.DbConfig

import com.improve_future.harmonica.core.Dbms

class Default: DbConfig({

dbms = Dbms.PostgreSQL

user = "developer"

password = "developer"

host = "127.0.0.1"

dbName = "harmonica_test"

})

Create Migration

You can create new migration with the following command.

./gradlew jarmonicaCreate

1	./gradlew jarmonicaCreate

If you want to specify the migration name, use migrationName property.

./gradlew jarmonicaCreate -PmigrationName=HelloWorld

1	./gradlew jarmonicaCreate -PmigrationName=HelloWorld

Then you can see the new migration file as follows.

package db.migration
import com.improve_future.harmonica.core.AbstractMigration
/**
* HolloWorld
*/
class M20180624011127699_HolloWorld : AbstractMigration() {
override fun up() {
createTable("table_name") {
integer("column_1")
varchar("column_2")
}
}
override fun down() {
dropTable("table_name")
}
}

package db.migration

import com.improve_future.harmonica.core.AbstractMigration

/**

* HolloWorld

class M20180624011127699_HolloWorld : AbstractMigration() {

override fun up() {

createTable("table_name") {

integer("column_1")

varchar("column_2")

}

override fun down() {

dropTable("table_name")

}

Migrate Up and Down

Now you can execute migration.

Up

./gradlew jarmonicaUp

1	./gradlew jarmonicaUp

Down

./gradlew jarmonicaDown

1	./gradlew jarmonicaDown

Warning

I checked the library with PostgreSQL. Not with MySQL.

The Life