Class: ConceptQL::Operators::Last

Inherits:

Occurrence

• Object
• Operator
• Occurrence
• ConceptQL::Operators::Last

Defined in:

lib/conceptql/operators/last.rb

Overview

Represents a operator that will grab the last occurrence of something

The operator treats all streams as a single, large stream. It partitions that larget stream by person_id, then sorts within those groupings by start_date and then select at most one row per person, regardless of how many different types of streams enter the operator

If two rows have the same start_date, the order of their ranking is arbitrary

If we ask for the last occurrence of something and a person has no occurrences, this operator returns nothing for that person

Constant Summary

Constants inherited from Operator

Operator::COLUMNS

Instance Attribute Summary

Attributes inherited from Operator

#arguments, #options, #upstreams, #values

Instance Method Summary

• #occurrence ⇒ Object

Methods inherited from Occurrence

#query

Methods inherited from Operator

#columns, #evaluate, #initialize, #label, #select_it, #set_values, #sql, #stream, #types

Methods included from Metadatable

#allows_many_upstreams, #allows_one_upstream, #argument, #category, #desc, #humanized_class_name, #inherited, #just_class_name, #option, #predominant_types, #preferred_name, #reset_categories, #to_metadata, #types

Constructor Details

This class inherits a constructor from ConceptQL::Operators::Operator

Instance Method Details

#occurrence ⇒ Object

# File 'lib/conceptql/operators/last.rb', line 20

def occurrence
  -1
end