Aris query Forumula and object definition

Hello,

I m trying to understand how to work with aris query and i have the two following question :

- I know there is a formula (REQUETE_ATTRIBUT_VALEUR(element, attribut) to display the attribut in the table view but i dont know how to use it to display for example the definition of an object resulting form the query (defintion of a function for example).
What do i need to set as element and attribut between () of the query. 
- Can i execute the query on the object definition level and not on the object occurance level.

Thanks

Omar