understanding arrow tips in MySQL Workbench EER diagram

mysql database database-design mysql-workbench yelp
cardamom picture cardamom · Nov 22, 2017 · Viewed 7k times · Source

I used the reverse-engineer function to generate an EER diagram of the Yelp dataset as per this question here. It looks like this:

EER diagram yelp dataset

Does anyone know exactly how to interpret it? What do the arrow tips mean, eg the one with 3 tips and a line, the one with 2 parallel lines. Then there are some without any tips.

Then, does the point at which the arrow enter or leave a table mean anything, eg one leaves the tip table around text and enters the checkin table around count, or is that irrelevant?

Another detail I noticed in there is that the yellow lightbulb is probably a primary key and the red diamond, a foreign key. Still can't see from the diagram however how the coloured symbols and arrows connect.

Answer

InfZero picture InfZero · Nov 22, 2017

Cardinality and ordinalitiy:

ERD Notation: Cardinality and Ordinality

Source: https://www.lucidchart.com/pages/ER-diagram-symbols-and-meaning

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