Now I stumbled several times over another notation, which I will try to illustrate:
where <> is kind of a rhombus, representing a "relationship-type". The cardinalities in parenthesises representing the (min,max). So one could think that, one city is in "n", where n is at least 1, countries.
That, I think, is just plain wrong. It is of course just the other way round. "n", where n is at least 1, cities are in one country (asuming that a country has at least one city, which is quite a safe asumption).
What am I misinterpreting?
Is this notation read backwards?
How would one design the city/country example in a "normal" ERD (with the first notation) ? Would it be something like this: country-1-----n-<city ?
There's nothing wrong with the example the left side shows the relationship of one country to many cities, the right side shows the relationship of one city to one country. In otherwords a country can have many cities, but a city of a certain name can exist in one and only one country.