From: Greg Ederer <greg_at_ergonosis.com>
Date: Tue, 07 Nov 2006 08:34:04 -0800

Hi,

I have a ManyToMany relationship between two classes, annotated like so at the owning end:

  @ManyToMany
  @JoinTable(name = "user_role", joinColumns =
    {@JoinColumn(name = "username", referencedColumnName = "username")},
     inverseJoinColumns = {@JoinColumn(name = "role_name", referencedColumnName = "name")})
  private List<Role> roles = new ArrayList<Role>();

At the other end:

  @ManyToMany(mappedBy="roles")
  private List<AppUser> appUsers = new ArrayList<AppUser>();

This produces the following join table (PostgreSQL):

CREATE TABLE user_role
(
  role_name varchar(255) NOT NULL,
  username varchar(255) NOT NULL,
  CONSTRAINT user_role_pkey PRIMARY KEY (role_name, username),
  CONSTRAINT fk_user_role_role_name FOREIGN KEY (role_name)
      REFERENCES "role" (name) MATCH SIMPLE
      ON UPDATE NO ACTION ON DELETE NO ACTION,
  CONSTRAINT fk_user_role_username FOREIGN KEY (username)
      REFERENCES app_user (username) MATCH SIMPLE
      ON UPDATE NO ACTION ON DELETE NO ACTION,
  CONSTRAINT user_role_username_key UNIQUE (username)
)

The user_role_username_key is unwanted.  How can I prevent it from being generated?

Thanks!

Greg