ORM supporting immutable classes

Question

Which ORM supports a domain model of immutable types?

I would like to write classes like the following (or the Scala equivalent):

class          


        

Answer 1

SORM is a new Scala ORM which does exactly what you want. The code below will explain it better than any words:

// Declare a model:
case class Artist ( name : String, genres : Set[Genre] )
case class Genre ( name : String ) 

// Initialize SORM, automatically generating schema:
import sorm._
object Db extends Instance (
  entities = Set() + Entity[Artist]() + Entity[Genre](),
  url = "jdbc:h2:mem:test"
)

// Store values in the db:
val metal = Db.save( Genre("Metal") )
val rock = Db.save( Genre("Rock") )
Db.save( Artist("Metallica", Set() + metal + rock) )
Db.save( Artist("Dire Straits", Set() + rock) )

// Retrieve values from the db:
val metallica = Db.query[Artist].whereEqual("name", "Metallica").fetchOne() // Option[Artist]
val rockArtists = Db.query[Artist].whereEqual("genres.name", "Rock").fetch() // Stream[Artist]