JPA 2: multiple column usage in foreign keys
You need to do this:
@ManyToOne@JoinColumns({ @JoinColumn(name="gameid", referencedColumnName = "gameid", insertable = false, updatable = false ), @JoinColumn(name="groupTag", referencedColumnName = "grouptag", insertable = false, updatable = false)})private Group group;EDIT: as mentioned in the comments, @JoinColumn is a repeatable annotation (since Java 8) that doesn't need wrapping. This simplifies the solution to:
@ManyToOne@JoinColumn(name="gameid", referencedColumnName = "gameid", insertable = false, updatable = false ),@JoinColumn(name="groupTag", referencedColumnName = "grouptag", insertable = false, updatable = false)private Group group;
Are you sure you can't use insertable = false, updateable = false for these @JoinColumns?
As far as I understand, you can initialize gameid once by setting game property, and after that you don't need to change it since Tiles and Groups belong to the same Game.