#1078 ✓resolved
bgentry

Document software (non-db) behavior of dm-constraints

Reported by bgentry | October 5th, 2009 @ 04:59 PM | in 0.10.2

The documentation does not explain the need to 'include DataMapper::Constraints' in a model in order to have DataMapper enforce the constraints on a software level (That is, without relying on the database constraints) so that constraints will still be enforced in non-FK databases like sqlite3.

Also, it may be helpful to explain how specifying a :destroy constraint should work for M:M relationships. Example:

class User
  has n, :group_users
  has n, :groups, :through => :group_users
end

class Group
  has n :group_users
  has n, :users, :through => :group_users
end

In the User class, where should the :destroy constraints be specified? On the intermediate :group_users model, or the final :groups model, or both? Docs seem to imply that both are necessary but should clarify this point.

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