HBM Hibernate many-to-many bidirectional connection with extra column - mysql

Question

i googled a lot and did follow many tutorials about it, but i didnt get it to work. I have a many-to-many relation between the table Player and Type. Both tables are connected via typeperplayer. In the table typeperplayer is an additional column paid, which i want to use in hibernate.
Here is the database scheme:
Player:
Play_ID : int
Play_FirstName : string
Play_LastName : string
Typeperplayer:
Typl_ID : int
Typl_Play_ID : int
Typl_Type_ID : int
Typl_Paid : int
Type
Type_ID : int
Type_Name : string
Here is my Hibernate-Mapping:
Player:
<hibernate-mapping>
<class name="de.tt.treg.server.domain.Player" table="player">
<id name="id" type="java.lang.Integer">
<column name="Play_ID" />
<generator class="identity" />
</id>
<property name="firstName" type="string">
<column name="Play_FirstName" length="255" not-null="false" unique="false" />
</property>
<property name="lastName" type="string">
<column name="Play_LastName" length="255" not-null="false" unique="false" />
</property>
<set name="competitions" table="typeperplayer"
inverse="true" lazy="false" fetch="select">
<key>
<column name="typl_play_id" not-null="true" />
</key>
<one-to-many class="de.tt.treg.server.domain.PlayerCompetition" />
</set>
</class>
PlayerCompetition (Typeperplayer)
<hibernate-mapping package="de.tt.treg.server.domain">
<class name="PlayerCompetition" table="typeperplayer">
<composite-id name="playerCompetitionPk"
class="PlayerCompetitionPk">
<key-property name="id" column="Typl_Play_Id"
type="java.lang.Integer" />
<key-property name="id" column="Typl_Type_Id"
type="java.lang.Integer" />
</composite-id>
<property name="paid" type="java.lang.Integer">
<column name="Typl_Paid" length="10" not-null="false" unique="false" />
</property>
<many-to-one name="player" class="Player" insert="false" update="false"/>
<many-to-one name="competition" class="Competition" insert="false" update="false"/>
</class>
Competition (Type):
<hibernate-mapping>
<class name="de.tt.treg.server.domain.Competition" table="type">
<id name="id" type="java.lang.Integer">
<column name="Type_ID" />
<generator class="identity" />
</id>
<property name="name" type="string">
<column name="Type_Name" length="255" not-null="false" unique="false" />
</property>
<set name="players" table="typeperplayer"
inverse="false" lazy="true" fetch="select">
<key>
<column name="Type_Id" not-null="true" />
</key>
<one-to-many class="de.tt.treg.server.domain.PlayerCompetition" />
</set>
</class>
Additionally here are my classes:
public class Player{
private int id;
private String firstName;
private String lastName;
private Set<PlayerCompetition> competitions = new HashSet<PlayerCompetition>();
public Player() {
}
public Player(String firstName, String lastName,
Set<PlayerCompetition> competitions) {
this.firstName = firstName;
this.lastName = lastName;
this.competitions = competitions;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public Set<PlayerCompetition> getCompetitions() {
return competitions;
}
public void setCompetitions(Set<PlayerCompetition> competitions) {
this.competitions = competitions;
}
}
public class PlayerCompetition {
private int id;
private int paid;
private PlayerCompetitionPk playerCompetitionPk;
public PlayerCompetition() {
}
public PlayerCompetition(int id, int paid,
PlayerCompetitionPk competitionPk) {
super();
this.id = id;
this.paid = paid;
this.playerCompetitionPk = competitionPk;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public int getPaid() {
return paid;
}
public void setPaid(int paid) {
this.paid = paid;
}
public PlayerCompetitionPk getPlayerCompetitionPk() {
return playerCompetitionPk;
}
public void setPlayerCompetitionPk(PlayerCompetitionPk playerCompetitionPk) {
this.playerCompetitionPk = playerCompetitionPk;
}
public Player getPlayer() {
return getPlayerCompetitionPk().getPlayer();
}
public void setPlayer(Player player) {
getPlayerCompetitionPk().setPlayer(player);
}
public Competition getCompetition() {
return getPlayerCompetitionPk().getCompetition();
}
public void setCompetition(Competition competition) {
getPlayerCompetitionPk().setCompetition(competition);
}
}
public class PlayerCompetitionPk {
private int id;
private Player player;
private Competition competition;
public PlayerCompetitionPk() {
}
public int getId() {
return id;
}
public Player getPlayer() {
return player;
}
public void setPlayer(Player player) {
this.player = player;
}
public Competition getCompetition() {
return competition;
}
public void setCompetition(Competition competition) {
this.competition = competition;
}
public void setId(int id) {
this.id = id;
}
}
public class Competition {
private int id;
private String name;
private Set<PlayerCompetition> players;
public Competition() {
}
public Competition(int id, String name) {
this.id = id;
this.name = name;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Set<PlayerCompetition> getPlayers() {
return players;
}
public void setPlayers(Set<PlayerCompetition> players) {
this.players = players;
}
}
I hope somebody can help me. If you need some additional information, you will get it ;-). Thank you.
Here is the generated sql statement:
select player0_.Play_ID as Play1_1_2_, player0_.Play_Club_ID as Play2_1_2_, player0_.Play_User_ID as Play3_1_2_, player0_.Play_FirstName as Play4_1_2_, player0_.Play_LastName as Play5_1_2_, player0_.Play_BirthDate as Play6_1_2_, team1_.Club_ID as Club1_0_0_, team1_.Club_Name as Club2_0_0_, team1_.Club_ShortName as Club3_0_0_, team1_.Club_Verband as Club4_0_0_, user2_.User_ID as User1_4_1_, user2_.User_Name as User2_4_1_, user2_.User_Passwort as User3_4_1_, user2_.User_RegisterDate as User4_4_1_ from player player0_ inner join club team1_ on player0_.Play_Club_ID=team1_.Club_ID inner join user user2_ on player0_.Play_User_ID=user2_.User_ID where player0_.Play_ID=?
In this statement are two joins with the other tables club and users. But there is no join with via typeperplayer.

Answer 1

The solution is to not directly map the player and type entities with a many-to-many relation, but instead have an intermediate entity playertype which you connect with one-to-many to both player and type.
That way you can use additional columns as properties on the playertype entity.
player <1-*> playertype <*-1> type
Edit:
Here's a nice example from mkyong
http://www.mkyong.com/hibernate/hibernate-many-to-many-example-join-table-extra-column-annotation/