Class: Cyrel::Clause::Unwind

Inherits:
Base
  • Object
show all
Defined in:
lib/cyrel/clause/unwind.rb

Overview

UNWIND clause for expanding lists into rows Like unpacking a suitcase, but for data and with less wrinkled clothes

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(expression, variable) ⇒ Unwind

Returns a new instance of Unwind.



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# File 'lib/cyrel/clause/unwind.rb', line 10

def initialize(expression, variable)
  @expression = expression
  @variable = variable.to_sym
end

Instance Attribute Details

#expression ⇒ Object (readonly)

Returns the value of attribute expression.



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# File 'lib/cyrel/clause/unwind.rb', line 8

def expression
  @expression
end

#variable ⇒ Object (readonly)

Returns the value of attribute variable.



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# File 'lib/cyrel/clause/unwind.rb', line 8

def variable
  @variable
end

Instance Method Details

#render(query) ⇒ Object 



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# File 'lib/cyrel/clause/unwind.rb', line 15

def render(query)
  cypher_parts = ['UNWIND']

  # Handle the expression
  expr_str = case @expression
             when Symbol
               # It's a parameter
               param_key = query.register_parameter(@expression)
               "$#{param_key}"
             when Array
               # Literal array
               "[#{@expression.map { |item| render_array_item(item, query) }.join(', ')}]"
             when Expression::Base
               # It's already an expression
               @expression.render(query)
             else
               # Try to coerce it
               Expression.coerce(@expression).render(query)
             end

  cypher_parts << expr_str
  cypher_parts << 'AS'
  cypher_parts << @variable.to_s

  cypher_parts.join(' ')
end