Java – Hibernate: two onetomany attributes mapped by the same entity with different columns

I know this can be easily solved through HQL query, but I prefer hibernate to handle some onetomany attributes for me

Let me demonstrate what I want my domain model to look like in pseudo code:

Game
  Long GameID
  Team HomeTeam
  Team AwayTeam
  @OneToMany(mappedBy="team")
  Set<TeamPlay> HomeTeamPlays
  @OneToMany(mappedBy="team")
  Set<TeamPlay> AwayTeamPlays

The table structure is similar, with two foreign keys pointing to the team table on the game table Obviously, if there is only one foreign key, it will represent a real one to many relationship, but in fact, what I want is two bidirectional one to many features of the same entity subtype

I don't believe the @ where annotation will work because it requires a constant and @ joincolumn is not allowed here If it's impossible, it doesn't matter. I just want to come from others

Solution

I bet you don't really understand the use of mappedby

You can https://stackoverflow.com/a/13812047/395202 Refer to my other answers in

In short, mappedby is the attribute name in the "opposite" of a two-way relationship

In your case, it may look like:

class TeamPlay {
    @ManyToOne
    Team homeTeam;

    @ManyToOne
    Team awayTeam;
}

class Team {
    @OneToMany(mappedBy="homeTeam")
    Set<TeamPlay> homeTeamPlays;

    @OneToMany(mappedBy="awayTeam")
    Set<TeamPlay> awayTeamPlays;
}