Question

I have a class A with a collection of other classes (B).

How do I represent in OCL that for each class (B) in the collection there’s a constraint on a field ?

I thought something like:

A.collection->iterate().field = SomeConstraint

Answer 1

Your terminology is a bit confusing. Do you mean you have something like

A———>* B

   bs

What do you expect SomeConstraint to be?

I guess you’re looking for so-called invariants in OCL for class A:

  context A
  inv allOK : bs->forall(b | ...)

Update:
If you want to count, the easiest way is not iterate, but doing select(...)->count(). Maybe that simplifies your matter.