Class: Veritas::Optimizer::Algebra::Product::TableDeeLeft

Inherits:

Veritas::Optimizer::Algebra::Product

• Object
• Veritas::Optimizer
• Relation::Operation::Binary
• Relation::Operation::Combination
• Veritas::Optimizer::Algebra::Product
• Veritas::Optimizer::Algebra::Product::TableDeeLeft

Defined in:

lib/veritas/optimizer/algebra/product.rb

Overview

Optimize when left operand is a TABLE DEE

Constant Summary

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 left operand is a TABLE DEE.

• #optimize ⇒ Relation private

  A Product with a left TABLE DEE is equivalent to the right operand.

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 left operand is a TABLE DEE

Returns:

• (Boolean)

# File 'lib/veritas/optimizer/algebra/product.rb', line 18

def optimizable?
  left = self.left
  left.header.empty? && !left.kind_of?(Veritas::Relation::Empty)
end

#optimize ⇒ Relation

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 Product with a left TABLE DEE is equivalent to the right operand

Returns:

• (Relation)

# File 'lib/veritas/optimizer/algebra/product.rb', line 28

def optimize
  right
end