All versions: 3.11 | 3.10 | 3.9 | 3.8 | 3.7 | Development versions: 3.12

As any other library, jOOQ can be easily used in Kotlin, taking advantage of the many Kotlin language features such as for example:

  • Optional ";" at the end of a Kotlin statement
  • Type inference for local variables

A short example jOOQ application in Kotlin might look like this:

package org.jooq.example.kotlin

import java.util.Properties

import org.jooq.*
import org.jooq.impl.DSL
import org.jooq.impl.DSL.*

import org.jooq.example.db.h2.Tables.*

fun main(args: Array<String>) {

    val properties = Properties();
    properties.load(Properties::class.java.getResourceAsStream("/config.properties"));

    DSL.using(
        properties.getProperty("db.url"),
        properties.getProperty("db.username"),
        properties.getProperty("db.password")
    ).use { ctx ->
        val a = AUTHOR
        val b = BOOK

        ctx.select(a.FIRST_NAME, a.LAST_NAME, b.TITLE)
           .from(a)
           .join(b).on(a.ID.eq(b.AUTHOR_ID))
           .orderBy(1, 2, 3)
           .forEach {
               println("${it[b.TITLE]} by ${it[a.FIRST_NAME]} ${it[a.LAST_NAME]}")
           }
    }
}

Note that Kotlin supports some means of operator overloading. For instance, a + b in Kotlin maps to a formal a.plus(b) method invocation, and jOOQ provides the required synonyms in its API to help you write such expressions.

One particularly nice language feature is the fact that [square brackets] allow for accessing any object's contents via get() and set() methods. Instead of using the above value1(), value2(), and value3() methods, we could also iterate as such:

        ctx.select(AUTHOR.FIRST_NAME, AUTHOR.LAST_NAME, BOOK.TITLE)
           .from(AUTHOR)
           .join(BOOK).on(AUTHOR.ID.eq(BOOK.AUTHOR_ID))
           .orderBy(1, 2, 3)
           .forEach {
               println("${it[BOOK.TITLE]} by ${it[AUTHOR.FIRST_NAME]} ${it[AUTHOR.LAST_NAME]}")
               // Notice:   ^^^^^^^^^^^^         ^^^^^^^^^^^^^^^^^^^      ^^^^^^^^^^^^^^^^^^
           }

A caveat of Kotlin operator overloading is the fact that operators such as == or >= map to a.equals(b), a.compareTo(b) == 0, a.compareTo(b) >= 0 respectively. This behaviour does not make sense in a fluent API such as jOOQ.

The jOOQ Logo