The Set functions are the instructions which define the group of instances for a query. These functions predicate functions, combining/merging functions, and relationship functions. Every set function returns a set reference (or SetRef for short) which can be materialized with the Paginate function, providing cursor semantics over the resulting set.
Set functions return ad hoc set predicates based on their arguments.
They can be composed to create more complex sets. The
function is used to access a set’s elements and historical timeline.