Class: ConceptQL::Operators::Intersect

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

Instance Attribute Summary

Attributes inherited from Operator

#arguments, #errors, #nodifier, #options, #upstreams, #values

Instance Method Summary collapse

Methods inherited from PassThru

#domains, #query_cols

Methods inherited from Operator

#annotate, #cast_column, #code_list, codes_should_match, #columns, #create_upstreams, #data_model, #database_type, default_query_columns, #domains, #dup_values, #dynamic_columns, #evaluate, inherited, #initialize, #inspect, #label, new, #operator_name, #optimized, query_columns, register, require_column, #required_columns, #scope, #select_it, #setup_select, #sql, #stream, #to_op, #unionable?, #upstreams_valid?, #valid?

Methods included from Metadatable

#allows_many_upstreams, #allows_one_upstream, #argument, #auto_label, #basic_type, #category, #derive_metadata_from_validations, #desc, #domains, #get_desc, #humanized_class_name, #inherited, #just_class_name, #no_desc, #option, #predominant_domains, #pref_name, #preferred_name, #reset_categories, #standard_description, #to_metadata, #validate_at_least_one_upstream_to_metadata, #validate_at_most_one_upstream_to_metadata, #validate_no_arguments_to_metadata, #validate_no_upstreams_to_metadata, #validate_one_upstream_to_metadata, #validate_required_options_to_metadata, #warn_about_missing_metadata

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/intersect.rb', line 15

def query(db)
  exprs = {}
  upstreams.each do |expression|
    evaled = expression.evaluate(db)
    expression.domains(db).each do |domain|
      (exprs[domain] ||= []) << evaled
    end
  end
  domained_queries = exprs.map do |domain, queries|
    queries.inject do |q, query|
      # Set columns so that impala's INTERSECT emulation doesn't use a query to determine them
      q.instance_variable_set(:@columns, query_cols)
      query.instance_variable_set(:@columns, query_cols)

      q.intersect(query)
    end
  end

  domained_queries.inject do |q, query|
    q.union(query, all: true)
  end
end