Entity, entitybase, entityService & CategoryService

[SamsDkh]

Hello,

First thank you for your effort to share your knowledge through this project.
What is the general purpose of Entity? Is it only to generate safeslug and keep a coherent infrastructure between different models in the database? Is there a pattern for this approach?
In CategoryService in Update and Delete why call, entity repository to do the required actions? And not the category repository like the creation through a single transaction?

Thank you

Samy