When your queries become more complex, entityLoad() just isnt robost or fluid enough to get the job done. In these more complex situations you may find yourself leaning on ormExecuteQuery and new Query() as an alternative to entityLoad()
Using a persistent entity's property formula attribute is pretty easy as long as you have all your persistent entity relationships properly set up.
We need develop the core entities that will serve as the backbone of the application. This is the part where we map our persistent entities to the database tables and columns. In its most basic form, creating persistent entities is really easy. However, the optional settings can get a little tricky and cause some headaches if they are done correctly.