Class: Locomotive::RelationalAlgebra::EquiJoin

Inherits:
Join show all
Defined in:
lib/locomotive/relational_algebra/operators/join/equi_join.rb

Instance Attribute Summary collapse

Attributes inherited from Operator

#schema

Attributes included from AstHelpers::AstNode

#kind, #left_child, #owner, #right_child, #value

Instance Method Summary collapse

Methods inherited from Operator

#bound, #free, #to_xml, #xml_schema

Methods included from XML

included, #quote, #to_xml

Methods included from AstHelpers::Annotations

#method_missing, #respond_to?

Methods included from AstHelpers::AstNode

#has_left_child?, #has_right_child?, #is_leaf?, #traverse, #traverse_strategy=

Constructor Details

#initialize(op1, op2, it1, it2) ⇒ EquiJoin

Returns a new instance of EquiJoin.



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# File 'lib/locomotive/relational_algebra/operators/join/equi_join.rb', line 12

def initialize(op1,op2,it1,it2)
  self.item1,
  self.item2 = it1, it2
  super(op1,op2)
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method in the class Locomotive::AstHelpers::Annotations

Instance Attribute Details

#item1 ⇒ Object

Returns the value of attribute item1.



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# File 'lib/locomotive/relational_algebra/operators/join/equi_join.rb', line 6

def item1
  @item1
end

#item2 ⇒ Object

Returns the value of attribute item2.



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# File 'lib/locomotive/relational_algebra/operators/join/equi_join.rb', line 8

def item2
  @item2
end

Instance Method Details

#clone ⇒ Object 



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# File 'lib/locomotive/relational_algebra/operators/join/equi_join.rb', line 45

def clone
  EquiJoin.new(left.clone,right.clone,
             item1.clone, item2.clone)
end

#left_and_right(op1, op2) ⇒ Object 



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# File 'lib/locomotive/relational_algebra/operators/join/equi_join.rb', line 18

def left_and_right(op1,op2)
  unless op1.schema.attributes?([self.item1])
    raise CorruptedSchema,
          "Schema #{op1.schema.attributes} does not " \
          "contain all attributes of #{item1}."
  end
  unless op2.schema.attributes?([self.item2])
    raise CorruptedSchema,
          "Schema #{op2.schema.attributes} does not " \
          "contain all attributes of #{item2}."
  end
  self.schema = op1.schema + op2.schema
  super(op1,op2)
end

#set(var, plan) ⇒ Object 



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# File 'lib/locomotive/relational_algebra/operators/join/equi_join.rb', line 50

def set(var,plan)
  EquiJoin.new(
    left.set(var,plan),
    right.set(var,plan),
    item1.clone,
    item2.clone)
end

#xml_content ⇒ Object 



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# File 'lib/locomotive/relational_algebra/operators/join/equi_join.rb', line 37

def xml_content
  content do
    [column(:name => item1.to_xml, :new => false, :position => 1),
     column(:name => item2.to_xml, :new => false, :position => 2)
    ].join
  end
end

#xml_kind ⇒ Object 



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# File 'lib/locomotive/relational_algebra/operators/join/equi_join.rb', line 33

def xml_kind
  :eqjoin
end