cheptsov / Select with a function and group by statement

Last active December 19, 2015 18:29

Just added function and group by support to the Expose SQL library for Kotlin

	select (Cities.name, сount(Users.id)) from Cities join Users groupBy Cities.name forEach {
	val (cityName, userCount) = it
	if (userCount > 0) {
	println("$userCount user(s) live(s) in $cityName")
	} else {
	println("Nobody lives in $cityName")
	}
	}

cheptsov / gist:6052798

Last active December 20, 2015 01:59

Support for type-safe wildcards in selects using Expose library

	object Cities : Table() {
	val id = id("id", autoIncrement = true)
	val name = varchar("name", 50)

	val all = id + name
	}

	select (Cities.all) forEach {
	val (id, name) = it
	println("$id: $name")

cheptsov / gist:6061029

Created July 23, 2013 09:08

Type-safe database table declaration using Kotlin language and Expose library

	object Users : Table() {
	val id = varchar("id", ColumnType.PRIMARY_KEY, length = 10) // PKColumn<String>
	val name = varchar("name", length = 50) // Column<String>
	val cityId = integer("city_id", ColumnType.NULLABLE, references = Cities.id) // Column<Int?>

	val all = id + name + cityId // Column3<String, String, Int?>
	}

	object Cities : Table() {
	val id = integer("id", ColumnType.PRIMARY_KEY, autoIncrement = true) // PKColumn<Int>

cheptsov / exposed-inner-join

Last active December 20, 2015 16:49

Type-safe inner join via Exposed library

	(Users.name + Users.cityId * Cities.name).filter { Users.id.equals("andrey") } forEach {
	val (userName, cityName) = it
	println("$userName lives in $cityName")
	}

cheptsov / gist:6777390

Last active December 24, 2015 09:29

Using Expose library to write select statements with inner and outer joins

	object Users : Table() {
	val id = varchar("id", length = 10).id() // PKColumn<String, Users>
	val name = varchar("name", length = 50) // Column<String, Users>
	val requiredCityId = integer("required_city_id").references(Cities.id) // FKColumn<Int, Users>
	val optionalCityId = integer("optional_city_id").references(Cities.id).optional() // FKOptionColumn<Int, Users>

	val all = id + name + requiredCityId + optionalCityId // Template4<Users, String, Int, Int?> Select template
	val values = id + name + requiredCityId + optionalCityId // Template4<Users, String, Int, Int?> Insert template
	}

cheptsov / gist:8124099

Last active January 1, 2016 09:19

A type-safe DSL for NoSQL using Kotlin language (experiment)

	import kotlin.nosql.*

	object Cities : Table() {
	val id = integer("id").id().generated() // GeneratedPKColumn<Int, Cities>
	val name = varchar("name", 50) // Column<String, Cities>

	val all = id + name // Template2<Cities, Int, String> Select template
	val values = name // Column<String, Cities>
	}

cheptsov / gist:8146503

Created December 27, 2013 12:42

Access Amazon DynamoDB using the type-safe Kotlin DSL for NoSQL databases. For more details: https://github.com/cheptsov/Exposed/tree/NoSQL

	import kotlin.nosql.*
	import kotlin.nosql.dynamodb.*

	object Users : Table() {
	val id = string("id", length = 10).id() // PKColumn<String, Users>
	val name = string("name", length = 50) // Column<String, Users>
	val requiredCityId = integer("required_city_id") // Column<Int, Users>
	val optionalCityId = integer("optional_city_id").nullable() // Column<Int?, Users>

	val all = id + name + requiredCityId + optionalCityId // Template4<Users, String, Int, Int?>

cheptsov / kotlin-nosql-roadmap.md

Last active August 29, 2015 13:57

Kotlin NoSQL Roadmap

v0.1

cheptsov / gist:e99e5fa7343143008b2b

Created July 6, 2014 22:03

Kotlin NoSQL API for MongoDB has been rewritten to use RxJava (see https://github.com/cheptsov/kotlin-nosql for details):

	// Get a document
	Albums.find { details.artistId.equal(artistId) }.subscribe(onNext = { album ->
	}, onError = {
	})

	// Get selected fields of a document
	Albums.find { id.equal(albumId) }.projection { sku + details.title + pricing }.subscribe(onNext = {
	val (sku, title, pricing) = it
	}, onError = {
	})

cheptsov / gist:0b2de0377430828db696

Created July 17, 2015 12:50

	(dao.topics outerJoin dao.comments on { case (topic, comment) => comment.topicId === topic.id }).list

	Results in

	play.api.Application$$anon$1: Execution exception[[SlickException: Expected a collection type, found UnassignedType]]
	at play.api.Application$class.handleError(Application.scala:296) ~[play_2.11-2.3.7.jar:2.3.7]
	at play.api.DefaultApplication.handleError(Application.scala:402) [play_2.11-2.3.7.jar:2.3.7]
	at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$14$$anonfun$apply$1.applyOrElse(PlayDefaultUpstreamHandler.scala:205) [play_2.11-2.3.7.jar:2.3.7]
	at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$14$$anonfun$apply$1.applyOrElse(PlayDefaultUpstreamHandler.scala:202) [play_2.11-2.3.7.jar:2.3.7]
	at scala.runtime.AbstractPartialFunction.apply(AbstractPartialFunction.scala:36) [scala-library-2.11.5.jar:na]