Class: ConceptQL::Operators::Except

Inherits:
BinaryOperatorOperator show all
Defined in:
lib/conceptql/operators/except.rb

Instance Attribute Summary

Attributes inherited from BinaryOperatorOperator

#left

Attributes inherited from Operator

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

Instance Method Summary collapse

Methods inherited from BinaryOperatorOperator

#code_list, #display_name, #upstreams

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/except.rb', line 11

def query(db)
  if ignore_dates?
    query = db.from(Sequel.as(left.evaluate(db), :l))
      .left_join(Sequel.as(right.evaluate(db), :r), l__criterion_id: :r__criterion_id, l__criterion_domain: :r__criterion_domain)
      .where(r__criterion_id: nil)
      .select_all(:l)
    db.from(query)
  else
    lquery = left.evaluate(db)
    rquery = right.evaluate(db)

    # Set columns so that impala's EXCEPT emulation doesn't use a query to determine them
    lquery.instance_variable_set(:@columns, query_cols)
    rquery.instance_variable_set(:@columns, query_cols)

    if impala?
      lquery = lquery.except_strategy(:not_exists, :person_id, :criterion_id, :criterion_domain)
    end
    lquery.except(rquery)
  end
end