Class: Linkage::Expectations::Filter

Inherits:
Simple show all
Defined in:
lib/linkage/expectations/simple.rb

Constant Summary

Constants inherited from Simple

Simple::VALID_OPERATORS

Instance Attribute Summary

Attributes inherited from Simple

#meta_object_1, #meta_object_2, #operator, #side

Instance Method Summary collapse

Methods inherited from Simple

create, #display_warnings, #exactly!, #initialize, #same_except_side?

Constructor Details

This class inherits a constructor from Linkage::Expectations::Simple

Instance Method Details

#apply_to(dataset, side) ⇒ Object 



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# File 'lib/linkage/expectations/simple.rb', line 102

def apply_to(dataset, side)
  if side != @side
    return dataset
  end

  dataset.filter(self.to_expr)
end

#decollation_needed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/linkage/expectations/simple.rb', line 110

def decollation_needed?
  false
end

#kind ⇒ Object 



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# File 'lib/linkage/expectations/simple.rb', line 89

def kind; :filter; end

#to_expr ⇒ Object 



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# File 'lib/linkage/expectations/simple.rb', line 91

def to_expr
  case @operator
  when :==, :'!='
    expr = { @meta_object_1.to_expr => @meta_object_2.to_expr }
    @operator == :== ? expr : ~expr
  else
    Sequel::SQL::BooleanExpression.new(@operator,
      @meta_object_1.to_identifier, @meta_object_2.to_identifier)
  end
end