Q: JPA layer - is there might be a need to use @OneToMany, @ManyToOne, @ManyToMany?

[asn25]

Hi Chris,

I'm checking JPA layer of FTGO application.
Could you please help me to clarify information on that.
In a number of previously seen applications I've encountered intensive usage of @onetomany, @manytoone, @manytomany (also with some following troubles and JPA Exceptions with Cascading problems on saving, especially for @manytomany).

In FTGO there are only:

• @Embedded (on a single object)
• @Embedded @ElementCollection (on a collection)

Questions are:

1. Why there is this difference in annotation usage? Maybe, because @OneToMany/@ManyToOne/@manytomany are used on related Entities - and in FTGO there is a concept of Aggregate introduced (central Entity with surrounding Value objects)?
2. Is it possible situation in FTGO when you have to use @OneToMany/@ManyToOne/@manytomany as well? Or FTGO JPA layer can live and work with @Embedded annotation only?

Thanks!