Class: Veritas::Optimizer::Algebra::Join::EqualHeaders

Inherits:

Veritas::Optimizer::Algebra::Join

• Object
• Veritas::Optimizer
• Relation::Operation::Binary
• Relation::Operation::Combination
• Veritas::Optimizer::Algebra::Join
• Veritas::Optimizer::Algebra::Join::EqualHeaders

Defined in:

lib/veritas/optimizer/algebra/join.rb

Overview

Optimize when operands’ headers are equal

Constant Summary

Constants inherited from Veritas::Optimizer::Algebra::Join

CONTRADICTION

Constants inherited from Veritas::Optimizer

Noop, VERSION

Instance Attribute Summary

Attributes included from Function::Binary

#left, #right

Attributes inherited from Veritas::Optimizer

#operation

Instance Method Summary

• #optimizable? ⇒ Boolean private

  Test if the operands’ headers are equal.

• #optimize ⇒ Algebra::Intersection private

  A Join with equal headers is an Intersection.

Methods included from Function::Binary

#initialize

Methods inherited from Veritas::Optimizer

chain, #initialize

Instance Method Details

#optimizable? ⇒ Boolean

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Test if the operands’ headers are equal

Returns:

• (Boolean)

# File 'lib/veritas/optimizer/algebra/join.rb', line 42

def optimizable?
  left.header.eql?(right.header)
end

#optimize ⇒ Algebra::Intersection

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

A Join with equal headers is an Intersection

Returns:

• (Algebra::Intersection)

# File 'lib/veritas/optimizer/algebra/join.rb', line 51

def optimize
  left.intersect(right)
end