ACTION_RESTRICT what this and other do (in your spare time)

For forum users having some spare time to answer. Documentation doesn't expand on it much yet:

Just would like to ask ( what do ACTION_RESTRICT additionally HAS_MANY_THROUGH tell/mean/do isThrough

Could ask more, but i need some idea about it now.


same with constraint created on database that actioned restrict on delete or on update


Thank you @xicond for information. Let the topic keep alive.