// Defaults:
Db4o.configure().activationDepth(5);
Db4o.configure().updateDepth(1);
Db4o.configure().objectClass(Person.class).cascadeOnActivate(false);
Db4o.configure().objectClass(Person.class).cascadeOnDelete(false);
Db4o.configure().objectClass(Person.class).cascadeOnUpdate(false);

// Vollständig manuelle Aktivierung:

Db4o.configure().activationDepth(0);
...
Person p = (Person)q.execute().next();
db.activate(p, 1);
p.mother.mother.doStuff() // NullPointerException!
db.deactivate(p, 1);