Two paths between two entities In my db the entities are:


designed_object: a generic designed object 
designed_object_param: a parameter related to the designed object with the type (param_type), the default value (param_value), the maximum and minimum value (param_max/min_value)
real_object: an instance of the designed object
real_object_param: the actual parameters of the instance (param_value)


They are related as follow (foreign key):


designed_object - real_object: 1..n
designed_object - designed_object_param: 1..n
real_object - real_object_param: 1..n
designed_object_param - real_object_param: 1..1


The problem is that there are two paths from real_object_param to designed_object:


real_object_param -> real_object -> designed_object
real_object_param -> designed_object_param -> designed_object


With this design, it is possible that, starting from the same real_object_param, the two paths point to two different rows if, for some bug, the real_object_param refers a wrong designed_object_param.
I know that this can be avoided through a trigger.
Is there any better design?

Thanks.
I renamed few things here, just to make it easier for me to think. Most of it is self-explanatory. In essence, the problem and the solution is very similar to the previous question, with more detailed answer.