Connect: Add Kotlin

Author: amotl

docs/_assets/icon/kotlin-logo.svg

@@ -73,6 +73,20 @@ CrateDB drivers and adapters for supported programming languages, frameworks, an
 {material-regular}`javascript;2em`
 ::::
 
+::::{grid-item-card} Kotlin
+:link: connect-kotlin
+:link-type: ref
+:link-alt: Connect to CrateDB using Kotlin
+:padding: 3
+:text-align: center
+:class-card: sd-pt-3
+:class-body: sd-fs-1
+:class-title: sd-fs-6
+```{image} /_assets/icon/kotlin-logo.svg
+:height: 50px
+```
+::::
+
 ::::{grid-item-card} PHP
 :link: connect-php
 :link-type: ref
@@ -184,6 +198,7 @@ application
 
 java
 javascript
+kotlin/index
 php
 python
 ruby

docs/connect/index.md

@@ -0,0 +1,107 @@
+(connect-kotlin)=
+
+# Kotlin
+
+:::{include} /_include/links.md
+:::
+
+:::{div} sd-text-muted
+Use JDBC to connect to CrateDB from Kotlin applications.
+:::
+
+:::{rubric} About
+:::
+
+:::
+[JDBC] is a standard Java API that provides a common interface for accessing
+databases in Java.
+:::
+
+:::{rubric} Driver options
+:::
+
+:::{div}
+Like when using {ref}`connect-java`, you have two JDBC driver options:
+The [PostgreSQL JDBC Driver] and the {ref}`crate-jdbc:index`.
+PostgreSQL JDBC uses the `jdbc:postgresql://` protocol identifier,
+while CrateDB JDBC uses `jdbc:crate://`.
+:::
+
+:::{rubric} Synopsis
+:::
+
+`example.kt`
+```kotlin
+import java.sql.DriverManager
+import java.util.*
+
+fun main() {
+
+    // Connect to database.
+    val jdbcUrl = "jdbc:postgresql://localhost:5432/doc?sslmode=disable"
+    val connection = DriverManager.getConnection(jdbcUrl, "crate", "crate")
+
+    // Invoke query.
+    val query = connection.prepareStatement("SELECT * FROM sys.summits ORDER BY height DESC LIMIT 3")
+    val result = query.executeQuery()
+
+    // Display results.
+    while (result.next()) {
+        val mountain = result.getString("mountain")
+        val height = result.getInt("height")
+        println("${mountain}: ${height}")
+    }
+
+}
+```
+`build.gradle.kts`
+```kotlin
+plugins {
+    java
+    kotlin("jvm") version "2.2.20"
+    application
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    runtimeOnly("org.postgresql:postgresql:42.7.8")
+}
+
+java {
+    toolchain {
+        languageVersion.set(JavaLanguageVersion.of(11))
+    }
+}
+
+application {
+    mainClass = "ExampleKt"
+}
+
+kotlin {
+    sourceSets.main {
+        kotlin.srcDir(".")
+    }
+}
+```
+
+Start CrateDB using Docker or Podman, then invoke the example program.
+```shell
+docker run --rm --publish=5432:5432 crate '-Cdiscovery.type=single-node'
+```
+```shell
+gradle run
+```
+
+:::{rubric} CrateDB Cloud
+:::
+
+For connecting to CrateDB Cloud, use `sslmode=require`, and
+replace username, password, and hostname with values matching
+your environment.
+```kotlin
+val jdbcUrl = "jdbc:postgresql://testcluster.cratedb.net:5432/doc?sslmode=require"
+val connection = DriverManager.getConnection(jdbcUrl, "admin", "password")
+```