1. A method of executing a query, comprising: (a) accessing, from a query execution data structure representative of a database query access plan for the query, at least one of a parent node object and a child node object from among a plurality of query node objects arranged into a tree relationship; and (b) manipulating at least a subset of a plurality of attributes referenced in an attribute data structure defined in the query execution data structure by processing at least one operation defined in an attribute operation data structure defined in the accessed node object, wherein processing the operation includes obtaining a reference for at least one attribute in the subset of attributes from the attribute data structure.