Play Framework - Example on how to use @onetomany with Ebean

1.sql

# --- Created by Ebean DDL
# To stop Ebean DDL generation, remove this comment and start using Evolutions

# --- !Ups

create table relation (
  id                        bigint not null,
  user_id                   bigint,
  constraint pk_relation primary key (id))
;

create table user (
  id                        bigint not null,
  constraint pk_user primary key (id))
;

create sequence relation_seq;

create sequence user_seq;

alter table relation add constraint fk_relation_user_1 foreign key (user_id) references user (id) on delete restrict on update restrict;
create index ix_relation_user_1 on relation (user_id);



# --- !Downs

SET REFERENTIAL_INTEGRITY FALSE;

drop table if exists relation;

drop table if exists user;

SET REFERENTIAL_INTEGRITY TRUE;

drop sequence if exists relation_seq;

drop sequence if exists user_seq;

Application.java

package controllers;

import models.Relation;
import models.User;
import play.*;
import play.mvc.*;

import views.html.*;

public class Application extends Controller {

    public static Result index() {


        User user = new User();
        Relation relation1 = new Relation();
        Relation relation2 = new Relation();

        user.relationList.add(relation1);
        user.relationList.add(relation2);
        user.save();

        Logger.debug("size of users: " + User.find.findRowCount());
        Logger.debug("size of relations: " + Relation.find.findRowCount());

        user.delete();

        Logger.debug("size of users: " + User.find.findRowCount());
        Logger.debug("size of relations: " + Relation.find.findRowCount());

        return ok(index.render("Your new application is ready."));
    }

}

console.log

[info] Set current project to demo (in build file:/private/tmp/demo/)
       _
 _ __ | | __ _ _  _
| '_ \| |/ _' | || |
|  __/|_|\____|\__ /
|_|            |__/

play 2.2.0 built with Scala 2.10.2 (running Java 1.7.0_51), http://www.playframework.com

> Type "help play" or "license" for more information.
> Type "exit" or use Ctrl+D to leave this console.

[demo] $ ~run

--- (Running the application from SBT, auto-reloading is enabled) ---

[info] play - Listening for HTTP on /0:0:0:0:0:0:0:0:9000

(Server started, use Ctrl+D to stop and go back to the console...)

[success] Compiled in 614ms
[info] play - database [default] connected at jdbc:h2:mem:play
[error] application - 

! @6i0a80g2f - Internal server error, for (GET) [/] ->

play.api.db.evolutions.InvalidDatabaseRevision: Database 'default' needs evolution![An SQL script need to be run on your database.]
	at play.api.db.evolutions.EvolutionsPlugin$$anonfun$onStart$1$$anonfun$apply$1.apply$mcV$sp(Evolutions.scala:486) ~[play-jdbc_2.10.jar:2.2.0]
	at play.api.db.evolutions.EvolutionsPlugin.withLock(Evolutions.scala:507) ~[play-jdbc_2.10.jar:2.2.0]
	at play.api.db.evolutions.EvolutionsPlugin$$anonfun$onStart$1.apply(Evolutions.scala:461) ~[play-jdbc_2.10.jar:2.2.0]
	at play.api.db.evolutions.EvolutionsPlugin$$anonfun$onStart$1.apply(Evolutions.scala:459) ~[play-jdbc_2.10.jar:2.2.0]
	at scala.collection.immutable.List.foreach(List.scala:318) ~[scala-library.jar:na]
	at play.api.db.evolutions.EvolutionsPlugin.onStart(Evolutions.scala:459) ~[play-jdbc_2.10.jar:2.2.0]
[info] play - database [default] connected at jdbc:h2:mem:play
[info] play - Application started (Dev)
[debug] application - size of users: 1
[debug] application - size of relations: 2
[debug] application - size of users: 0
[debug] application - size of relations: 0

Relation.java

package models;

import play.db.ebean.Model;

import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.ManyToOne;

/**
 * Created by jan on 2014-04-16.
 */
@Entity
public class Relation extends Model {
    @Id
    public Long id;

    @ManyToOne
    public User user;

    public static Finder<Long,Relation> find = new Finder( Long.class, Relation.class );
}

User.java

package models;

import play.db.ebean.Model;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import java.util.ArrayList;
import java.util.List;

/**
 * Created by jan on 2014-04-16.
 */
@Entity
public class User extends Model {
    @Id
    public Long id;

    @OneToMany(cascade = CascadeType.ALL)
    public List<Relation> relationList = new ArrayList<>();


    public static Finder<Long,User> find = new Finder( Long.class, User.class );
}