Crows Feet, for simple ERD


#1

A simple version of Entity-Relationship Diagram (ERD) use “Crows Feet” notation.

https://en.wikipedia.org/wiki/Entity–relationship_model#Crow’s_foot_notation

example of crows feet line endings

Each end of a line should offer a triple-spike (optional). Behind that, on the line, should be a vertical bar (meaning 1), and an “O” or zero (meaning zero), both optional. Or a pair of vertical bars (meaning one and only one).

The lines hook up to boxes listing the names and fields of entities/tables. The lines should intelligently wrap around boxes using right angles.

I have found some crude crows feet templates for OmniGraffle but they were clunky, did not look good, the triple-spike (crow’s toes) did not align to the target box, and were difficult to use. A great disappointment to this paying customer since an ERD is one of the most common kinds of diagrams I would expect from a diagramming application like OmniGraffle.

It would be nice to have a box for the entities/tables, a box with a row at the top for the entity/table name, and a two-column list below for each attribute and data-type. Bonus points for some attractive subtle coloring and background shading, as well as plain black-and-white.


#2

I just want to make sure first that you saw that you can change the line type in the Line inspector, and there are crow’s-feet line types there.


#3

Having the crows foot as a line end is a great feature although you will still have to add objects to show the more specific relationship. The UML equivalent of the ERD (class diagram) also needs special lines, ie solid at one end and dashed at the other.