Yii's by-default directory organization works well enough, but there are several steps one can take that improve the security and serviceability of the system, especially in the context of multiple Yii projects on the same machine (including multiple versions of the same project).
Please consider the following
Dear software engineers imagine I have a simple ISA hierarchy: parent A with
children B and C.
So let's say we have the corresponding tables named "a", "b", "c" and (created
with the help of the gii model creator) the classes A, B, C
The following is a screenshot from MySQL workbench: