There is no "standard" ER diagram. Many others, in addition to the three described above are in use.
Fortunately, once you have learned to interpret one of them, it is fairly easy to learn how to read any of the others.
In this module, you will work exclusively with the Crowsfoot model.
The next lesson illustrates the conventions used to diagram entities and attributes with the Crowsfoot model.
Before moving on to the next lesson, click the link below to see if you can identify the three best-known types of ER diagrams.
idef1x Crowsfoot | Chen-model