sromscala的orm框架

scala的orm框架，相比其他orm更为简洁

// 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:
// Option[Artist with Persisted]:
val metallica = Db.query[Artist].whereEqual("name", "Metallica").fetchOne() 
// Stream[Artist with Persisted]:
val rockArtists = Db.query[Artist].whereEqual("genres.item.name", "Rock").fetch()