This module includes:

• The vok-util-vaadin module which includes Vaadin-related utilities for pleasant Kotlin development of Vaadin-based app,
• The vok-orm project which includes SQL database support,
• The jdbi-orm-vaadin project which provides several utility methods to provide nice integration of Vaadin with the SQL database, namely the Grid filters and Grid DataProvider.

To use this module in your app just add the following dependency into your build.gradle file:

dependencies {
    compile("eu.vaadinonkotlin:vok-framework-vokdb:x.y.z")
}

Note: to obtain the newest version see above for the most recent tag

This module provides:

• Dao.dataProvider which returns EntityDataProvider for an entity. You usually make KEntity's companion object extend the Dao; if you do, this extension property will allow you to obtain the DataProvider for an KEntity simply by calling Person.dataProvider.
• EntityToIdConverter which is useful when binding a ComboBox<Person> to a Long field which only contains the person ID.

Use this module if you intend to build a Vaadin-based app which accesses your SQL database.

Note: There is no support for Vaadin + JPA in VoK.

If you plan to use NoSQL database or some other form of data fetching, then only use the vok-util-vaadin module. You will then have to write your own data fetching layer; however you may find inspiration on how to do so, by checking the sources of this module.

First you will need to add the JDBC driver for your database as a dependency to your build.gradle.kts file. Then, you'll need to add Hikari-CP as a dependency (unless you're running on Spring/JavaEE):

implementation("com.zaxxer:HikariCP:5.0.1")

After that's done, you need to configure the vok-db database JDBC provider. The following example configures an in-memory H2 database:

val config = HikariConfig().apply {
    driverClassName = Driver::class.java.name  // the org.h2.Driver class
    jdbcUrl = "jdbc:h2:mem:test;DB_CLOSE_DELAY=-1"
    username = "sa"
    password = ""
}
VaadinOnKotlin.dataSource = HikariDataSource(config)

It is a good practice to run the configuration from your ServletContextListener. You can find a proper example in the Beverage Buddy's Bootstrap class.

Don't forget to close the data source and clean up resources properly, in your ServletContextListener.contextDestroyed() function:

JdbiOrm.destroy()

It is recommended to run database migrations from your ServletContextListener as well, to make sure that the database structure is up-to-date.

This module does not provide any support for migrations directly, however adding the support for migrations to your app is extremely easy.

The easiest way is to use Flyway. Just add the following to your build.gradle file:

dependencies {
    implementation("org.flywaydb:flyway-core:9.22.3")
}

Now we can add SQL scripts to your src/main/resources/db/migration folder; simply create a file named V01__CreateCategory.sql in there, with the following contents:

create TABLE CATEGORY (
  id bigint auto_increment PRIMARY KEY,
  name varchar(200) NOT NULL,
);
create UNIQUE INDEX idx_category_name ON CATEGORY(name);

Please find more documentation in the Flyway Migration Guide.

To actually run the migration, you will need to call the Flyway class, ideally from your ServletContextListener after VoK is initialized:

val flyway = Flyway.configure()
    .dataSource(VaadinOnKotlin.dataSource)
    .load()
flyway.migrate()

Please see the Beverage Buddy's Bootstrap for more details.

• The Accessing Database Guide
• The Using Grids Guide