exposed-dao-r2dbc/org.jetbrains.exposed.v1.dao.r2dbc/Accessor

Accessor

class Accessor<ID : Any, Parent : Entity<ID>, REF : Any>(reference: Column<REF>, factory: EntityClass<ID, Parent>, entity: Entity<*>, references: Map<Column<*>, Column<*>>? = null)

What a non-nullable many-to-one reference declared with referencedOn gives back. Declare the property as a val, read the referenced entity by invoking it, and write it with set:

class Film(id: EntityID<Int>) : IntEntity(id) {
    val director by Director referencedOn Films.director

    companion object : IntEntityClass<Film>(Films)
}

val name = film.director().name   // suspends, and queries unless the entity is already cached
film.director.set(otherDirector)  // does not suspend: staged like any other column write

The property hands back this accessor rather than the entity itself because reading it has to suspend and a property getter cannot — the JDBC DAO, where the read blocks, returns the entity directly.

Constructors

Accessor

constructor(reference: Column<REF>, factory: EntityClass<ID, Parent>, entity: Entity<*>, references: Map<Column<*>, Column<*>>? = null)

Functions

getValue

operator fun getValue(thisRef: Any?, property: KProperty<*>): Accessor<ID, Parent, REF>

Property delegate operator — returns this accessor itself, used to expose invoke / set.

invoke

suspend operator fun invoke(): Parent

Suspending read of the referenced parent entity. Looks up the entity from the cache, or otherwise resolves the parent by querying the database via factory.

set

fun set(value: Parent)

Writes the link to value into the underlying reference column(s) and pins it in the entity's reference cache.