42+ Design Er Diagram Symbols Example Download Zip Background. What do they mean and what are they used for? So you want to learn entity relationship diagrams?
Using standardized er diagram symbols helps you save time and more clearly communicate with your team.
U symbol indicates the subtype is a subset of the supertype. An er diagram shows the relationship among entity sets. This is illustrated in the example execution below: Using standardized er diagram symbols helps you save time and more clearly communicate with your team.