| relateB(B) | Looks in the table for object b, and finds the object a that is related. Returns the found object, or throws an exception if not found |
| relateB(B, A) | Looks in the table for object b, and finds the object a that is related. Returns true if found, false if not found. Remark: Named relateB, since, if A and B is same type then relateA and relateB can not be distinguished without the A/B in the end |