Hi,
This is my db schema which looks like this:
So a staff (which is a teacher) can teach a specific subject (curriculum) to a specific class (class_id).
As you can see 'teaches' is the table where all the tables meet. I've tried the Dali tool and it did a pretty good job, by producing something like this (The 'Staff' entity, not entirely quoted, just the parts which have to do with 'teaches'):
//uni-directional many-to-many association to Curriculum
@ManyToMany
@JoinTable(
name="teaches"
, joinColumns={
@JoinColumn(name="staff_id", referencedColumnName="staff_id"),
}
, inverseJoinColumns={
@JoinColumn(name="class", referencedColumnName="class"),
@JoinColumn(name="subject_id", referencedColumnName="subject_id"),
@JoinColumn(name="year", referencedColumnName="year"),
}
)
private Set<Curriculum> curriculums;
//bi-directional many-to-many association to Class
@ManyToMany
@JoinTable(
name="teaches"
, joinColumns={
@JoinColumn(name="staff_id", referencedColumnName="staff_id"),
}
, inverseJoinColumns={
@JoinColumn(name="class_id", referencedColumnName = "class_id"),
}
)
private Collection<Class> clazzs;But this makes problem when I want to persist a new Staff object, which 'teaches' a specific subject (year, class, subject_id) to a specific class_id, because it doesn't know which class_id with which subject go together. Could you please help me with a better solution for this?
Help is appreciated
Sincerely yours,
tomor
