I have a table that has two different many-to-many relations to two different tables. Let's say I have User
<---> UserRole
<--> Role
and User
<--> UserGroups
<--> Groups
. Since I am new to hibernate and database mapping I was wondering if having my User
entity have attributes roles and groups in it, both with @ManytoMany
annotations is good practice and acceptable?
ie:
@Entity(name = "User")
@Table(name = "USER")
public class User {
.... /* Obviously Id would go here and all other attributes */
@ManyToMany(cascade = CascadeType.ALL)
@JoinTable(name = "UserRole", joinColumns = { @JoinColumn(name="USER_ID") },
inverseJoinColumns = { @JoinColumn(name = "ROLE_ID") } )
private Set<Role> roles = new HashSet<Role>();
@ManyToMany(cascade = CascadeType.ALL)
@JoinTable(name = "UserGroup", joinColumns = { @JoinColumn(name="USER_ID") },
inverseJoinColumns = { @JoinColumn(name = "GROUP_ID") } )
private Set<Group> groups = new HashSet<Group>();
Sure; lots of types have multiple many-to-many.
I think minimizing many-to-many relationships is a good idea, but it's a natural structure, and is found all over the place.
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