Class: ConceptQL::Operators::Complement

Inherits:
PassThru show all
Defined in:
lib/conceptql/operators/complement.rb

Constant Summary

Constants inherited from Operator

Operator::COLUMNS

Instance Attribute Summary

Attributes inherited from Operator

#arguments, #options, #upstreams, #values

Instance Method Summary collapse

Methods inherited from PassThru

#types

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

#query(db) ⇒ Object 



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# File 'lib/conceptql/operators/complement.rb', line 10

def query(db)
  upstream = upstreams.first
  upstream.types.map do |type|
    positive_query = db.from(upstream.evaluate(db))
      .select(:criterion_id)
      .exclude(:criterion_id => nil)
      .where(:criterion_type => type.to_s)
    query = db.from(make_table_name(type))
      .exclude(make_type_id(type) => positive_query)
    db.from(select_it(query, type))
  end.inject do |union_query, q|
    union_query.union(q, all: true)
  end
end

#query2(db) ⇒ Object

This is an alternate, but equally accurate way to do complement. We’ll need to benchmark which is faster.



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# File 'lib/conceptql/operators/complement.rb', line 28

def query2(db)
  upstream = upstreams.first
  froms = upstream.types.map do |type|
    select_it(db.from(make_table_name(type)), type)
  end
  big_from = froms.inject { |union_query, q| union_query.union(q, all:true) }
  db.from(big_from).except(upstream.evaluate(db))
end