The "normal" appearance of an ERD, like I know it, can be seen on here:
http://www.utexas.edu/its/windows/da...m/erintro.html
on the bottom of the page, right above "Summary"
Now I stumbled several times over another notation, which I will try to illustrate:
country--(1,n)---<is in>---(1,1)--city
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 ?