exposed-wiki/DSL.md

The DSL (Domain Specific Language) API of Exposed, is similar to actual SQL statements with type safety that Kotlin offers.
A DB table is represented by an object inherited from org.jetbrains.exposed.sql.Table like that:

object StarWarsFilms : Table() {
  val id: Column<Int> = integer("id").autoIncrement().primaryKey()
  val sequelId: Column<Int> = integer("sequel_id").uniqueIndex()
  val name: Column<String> = varchar("name", 50)
}

Tables that contains Int id with the name id can be declared like that:

object StarWarsFilms : IntIdTable() {
  val sequelId: Column<Int> = integer("sequel_id").uniqueIndex()
  val name: Column<String> = varchar("name", 50)
}

Basic CRUD operations

Create

val id = StarWarsFilms.insert {
  it[name] = "The Last Jedi"
  it[sequelId] = 8
} get StarWarsFilms.id

Read

val query: Query = StarWarsFilms.select { StarWarsFilms.sequelId eq 8 }

Query inherit Iterable so it is possible to traverse it with map/foreach etc'

Update

StarWarsFilms.update ({ StarWarsFilms.sequelId eq 8 }) {
  it[name] = "Episode VIII – The Last Jedi"
}

Delete

StarWarsFilms.deleteWhere { StarWarsFilms.sequelId eq 8 }

Where expression

Query expression (where) expects a boolean operator (ie: Op<Boolean>).
Allowed conditions are:

eq - (==)
neq - (!=)
isNull()
isNotNull()
less - (<)
lessEq - (<=)
greater - (>)
greaterEq - (>=)
like - (=~)
notLike - (!~)
regexp
notRegexp
inList
notInList
between
match (MySQL MATCH AGAINST) 

Allowed logical conditions are:

and
or

Advanced operations

Join