I am am new to Toad Data Modeler so my apologies for the slew of questions.
This one is about the meaning of the tiny icons in the Explorer for entities (and even other objects, but I have not seen any yet)
I tried to find in the documentation, but so far I was not able to find it. So if it is there, please point me tot he correct sections. Searching on "icon" of "explorer" did not give me the answers I looked for.
TDM allows you to verify your model and each model contains a set of rules which are considered during verification. You can perform manual verification (CTRL+F9) or use an automatic verification during generating of DDL script (you can turn off it in Option | Model | Physical Model SQL Generation Script).