ERD (Entity-relationship model) - Need an example for a prob that can not be modeled by it

I got a weird H.W assignment in requirements engineering seminar .

I was digging through the entire net yet found no example for this one...

I need to find a problem from any engineering field (mechanics,medicine,chemistry,programming etc.) that the ERD model fails to give a complete/any answer to.

Can anyone show me some examples of a loss of information/process/entity while modeling only in ERD ?

maybe a point where I will 开发者_如何转开发need to compromise in order to continue modeling?

Or at least what are ERD's limitations ?

I need it to be an example for the limitation/disadvantage and not an example for a common mistake or bad modeling.

Well, ERD only deals with static aspects of the problem (i.e. the structure of the data that needs to be manipulated). All the information about the dynamic aspects of the problem will be lost if you only model using ERD