All the methods can be divided into 2 main categories:
Event methods - methods available just inside events' handler functions (different events provide different methods. The appropriate ones depend on input object).
DataAction Object - relates to action queries. Input object of: beforeInsert, beforeUpdate, beforeDelete, beforeProcessing, afterProcessing, afterDelete, afterUpdate, afterInsert events.
DataItem Object - relates to using dhtmlx component.
Input object of: beforeRender event.
Input object of: beforeSort event.
Input object of: beforeFilter event.