Hello All - Wondering if someone can help me. Here's my setup briefly. I have a OneToMany between a Challenge and Participants. The challenge has a auto-increment PK id. The Participants have a composite primary key between an id (from challenge's PK) and user_email. Participants also has a FK to Challenge's id.

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Challenge Table
id_challenge - PK Auto-Increment
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Participants Table
id_challenge - PK
user_email - PK
fk_id - FK to Challenge.id
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@IdClass(ChallengeParticipantPK.class)
public class Participants{
@ManyToOne()
@JoinColumn(name="id_challenge", insertable=false, updatable=false)
Challenge challenge;
@Id
@Column(name="id_challenge")
int id;
@Id
String email;
}
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public class Challenge{
@OneToMany( cascade=CascadeType.ALL, mappedBy="id")
Set<ChallengeParticipant> participants;
}

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When I run this, it does an insert into challenge (good), then a select from participants(BAD), then an insert into participants(good). I was thinking it should do the insert, then select from challenge to find the last UID inserted for challenge, then insert participants. Needless to say, I'm getting a foreign key constraint error on id_challenge in participant. Can anyone help? Is it a bad idea to have a composite primary key when you have a foreign key with one of those composite keys?

Any help would be appreciated.
Thanks