Class: ActiveCypher::Relationship

Inherits:
Object
  • Object
show all
Includes:
Logging, Model::Abstract, Model::Callbacks, Model::ConnectionHandling, Model::ConnectionOwner, Model::Countable, ActiveModel::API, ActiveModel::Attributes, ActiveModel::Dirty, ActiveModel::Naming, ActiveModel::Validations
Defined in:
lib/active_cypher/relationship.rb

Direct Known Subclasses

ApplicationGraphRelationship

Constant Summary

Constants included from Model::Callbacks

Model::Callbacks::EVENTS

Class Attribute Summary collapse

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Logging

#log_bench, #log_debug, #log_error, #log_info, #log_warn, #logger, logger

Methods included from Model::ConnectionOwner

#adapter_class, #connection

Constructor Details

#initialize(attrs = {}, from_node: nil, to_node: nil, **attribute_kwargs) ⇒ Relationship

Returns a new instance of Relationship.



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# File 'lib/active_cypher/relationship.rb', line 267

def initialize(attrs = {}, from_node: nil, to_node: nil, **attribute_kwargs)
  _run(:initialize) do
    super()

    # Merge explicit attrs hash with keyword arguments for attributes.
    # Note: `attribute_kwargs` takes precedence over `attrs` for keys that exist in both.
    combined_attrs = attrs.merge(attribute_kwargs)
    assign_attributes(combined_attrs) if combined_attrs.any?

    @from_node  = from_node
    @to_node    = to_node
    @new_record = true
    clear_changes_information
  end
end

Class Attribute Details

.last_internal_id ⇒ Object (readonly)

Returns the value of attribute last_internal_id.



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# File 'lib/active_cypher/relationship.rb', line 88

def last_internal_id
  @last_internal_id
end

Instance Attribute Details

#from_node ⇒ Object

Life‑cycle



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# File 'lib/active_cypher/relationship.rb', line 264

def from_node
  @from_node
end

#new_record ⇒ Object (readonly)

Returns the value of attribute new_record.



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# File 'lib/active_cypher/relationship.rb', line 265

def new_record
  @new_record
end

#to_node ⇒ Object

Life‑cycle



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# File 'lib/active_cypher/relationship.rb', line 264

def to_node
  @to_node
end

Class Method Details

.connection ⇒ Object

Connection fallback

Relationship classes usually share the same Bolt pool as the node they originate from; delegate there unless the relationship class was given its own pool explicitly.

WorksAtRelationship.connection  # -> PersonNode.connection



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# File 'lib/active_cypher/relationship.rb', line 68

def self.connection
  # If a node_base_class is set (directly or by convention), always delegate to its connection
  if (klass = node_base_class)
    return klass.connection
  end

  return @connection if defined?(@connection) && @connection

  from_class.constantize.connection
end

.create(attrs = {}, from_node:, to_node:, **attribute_kwargs) ⇒ Object

– factories ———————————————– Mirrors ActiveRecord.create



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# File 'lib/active_cypher/relationship.rb', line 155

def create(attrs = {}, from_node:, to_node:, **attribute_kwargs)
  new(attrs, from_node: from_node, to_node: to_node, **attribute_kwargs).tap(&:save)
end

.create!(attrs = {}, from_node:, to_node:, **attribute_kwargs) ⇒ Object

Bang version of create - raises exception if save fails For when you want your relationship failures to be as dramatic as your breakups



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# File 'lib/active_cypher/relationship.rb', line 161

def create!(attrs = {}, from_node:, to_node:, **attribute_kwargs)
  relationship = create(attrs, from_node: from_node, to_node: to_node, **attribute_kwargs)
  if relationship.persisted?
    relationship
  else
    error_msgs = relationship.errors.full_messages.join(', ')
    error_msgs = 'Validation failed' if error_msgs.empty?
    raise ActiveCypher::RecordNotSaved,
          "#{name} could not be saved: #{error_msgs}. " \
          "Perhaps the nodes aren't ready for this kind of commitment?"
  end
end

.find_by(attributes = {}) ⇒ Object

– Querying methods —————————————- Find the first relationship matching the given attributes Like finding a needle in a haystack, if the haystack was made of graph edges



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# File 'lib/active_cypher/relationship.rb', line 187

def find_by(attributes = {})
  return nil if attributes.blank?

  rel_type = relationship_type

  # Build WHERE conditions for the attributes
  conditions = []
  params = {}

  attributes.each_with_index do |(key, value), index|
    param_name = :"p#{index + 1}"
    conditions << "r.#{key} = $#{param_name}"
    params[param_name] = value
  end

  where_clause = conditions.join(' AND ')

  # Determine ID function based on adapter type
  adapter_class = connection.class
  id_func = adapter_class.const_defined?(:ID_FUNCTION) ? adapter_class::ID_FUNCTION : 'id'

  cypher = "    MATCH ()-[r:\#{rel_type}]-()\n    WHERE \#{where_clause}\n    RETURN r, \#{id_func}(r) as rid, startNode(r) as from_node, endNode(r) as to_node\n    LIMIT 1\n  CYPHER\n\n  result = connection.execute_cypher(cypher, params, 'Find Relationship By')\n  row = result.first\n\n  return nil unless row\n\n  # Extract relationship data and instantiate\n  rel_data = row[:r] || row['r']\n  rid = row[:rid] || row['rid']\n\n  # Extract properties from the relationship data\n  # Memgraph returns relationships wrapped as [type_code, [actual_data]]\n  attrs = {}\n\n  if rel_data.is_a?(Array) && rel_data.length == 2\n    # Extract the actual relationship data from the second element\n    actual_data = rel_data[1]\n\n    if actual_data.is_a?(Array) && actual_data.length >= 5\n      # Format: [rel_id, start_id, end_id, type, properties, ...]\n      props = actual_data[4]\n      attrs = props.is_a?(Hash) ? props : {}\n    end\n  elsif rel_data.is_a?(Hash)\n    attrs = rel_data\n  end\n\n  # Convert string keys to symbols for attributes\n  attrs = attrs.transform_keys(&:to_sym)\n  attrs[:internal_id] = rid if rid\n\n  instantiate(attrs)\nend\n"

.find_by!(attributes = {}) ⇒ Object

Find the first relationship or raise an exception For when nil just isn’t dramatic enough for your data access needs



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# File 'lib/active_cypher/relationship.rb', line 250

def find_by!(attributes = {})
  # Format attributes nicely for the error message
  formatted_attrs = attributes.map { |k, v| "#{k}: #{v.inspect}" }.join(', ')

  find_by(attributes) || raise(ActiveCypher::RecordNotFound,
                               "Couldn't find #{name} with #{formatted_attrs}. " \
                               'Maybe these nodes were never meant to be connected? ' \
                               'Or perhaps their relationship status is... complicated?')
end

.from_class(value = nil) ⇒ Object Also known as: from_class_name

– endpoints ————————————————



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# File 'lib/active_cypher/relationship.rb', line 131

def from_class(value = nil)
  return _from_class_name if value.nil?

  self._from_class_name = value.to_s
end

.inherited(subclass) ⇒ Object

Prevent subclasses from overriding node_base_class



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# File 'lib/active_cypher/relationship.rb', line 120

def inherited(subclass)
  super
  return unless _node_base_class

  subclass._node_base_class = _node_base_class
  def subclass.node_base_class(*)
    raise "Cannot override node_base_class in subclass #{name}; it is locked to #{_node_base_class}"
  end
end

.instantiate(attributes, from_node: nil, to_node: nil) ⇒ Object

Instantiate from DB row, marking the instance as persisted.



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# File 'lib/active_cypher/relationship.rb', line 175

def instantiate(attributes, from_node: nil, to_node: nil)
  instance = allocate
  instance.send(:init_with_attributes,
                attributes,
                from_node: from_node,
                to_node: to_node)
  instance
end

.node_base_class(klass = nil) ⇒ Object

DSL for setting or getting the node base class for connection delegation



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# File 'lib/active_cypher/relationship.rb', line 91

def node_base_class(klass = nil)
  if klass.nil?
    # If not set, try convention: XxxRelationship -> XxxNode
    return _node_base_class if _node_base_class

    if name&.end_with?('Relationship')
      node_base_name = name.sub(/Relationship\z/, 'Node')
      begin
        node_base_klass = node_base_name.constantize
        if node_base_klass.respond_to?(:abstract_class?) && node_base_klass.abstract_class?
          self._node_base_class = node_base_klass
          return node_base_klass
        end
      rescue NameError
        # Do nothing, fallback to nil
      end
    end
    return _node_base_class
  end
  # Only allow setting on abstract relationship base classes
  raise "Cannot set node_base_class on non-abstract relationship class #{name}" unless abstract_class?
  unless klass.respond_to?(:abstract_class?) && klass.abstract_class?
    raise ArgumentError, "node_base_class must be an abstract node base class (got #{klass})"
  end

  self._node_base_class = klass
end

.to_class(value = nil) ⇒ Object Also known as: to_class_name 



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# File 'lib/active_cypher/relationship.rb', line 138

def to_class(value = nil)
  return _to_class_name if value.nil?

  self._to_class_name = value.to_s
end

.type(value = nil) ⇒ Object Also known as: relationship_type

– type —————————————————–



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# File 'lib/active_cypher/relationship.rb', line 146

def type(value = nil)
  return _relationship_type if value.nil?

  self._relationship_type = value.to_s.upcase
end

Instance Method Details

#destroy ⇒ Object 



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# File 'lib/active_cypher/relationship.rb', line 324

def destroy
  _run(:destroy) do
    raise 'Cannot destroy a new relationship' if new_record?
    raise 'Relationship already destroyed'    if destroyed?

    adapter = self.class.connection.id_handler

    cypher = "MATCH ()-[r]-() WHERE #{adapter.with_direct_id(internal_id)} DELETE r"
    params = {}

    self.class.connection.execute_cypher(cypher, params, 'Destroy Relationship')
    @destroyed = true
    freeze
    true
  end
rescue StandardError => e
  log_error "Failed to destroy #{self.class}: #{e.class} – #{e.message}"
  false
end

#destroyed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_cypher/relationship.rb', line 285

def destroyed?   = @destroyed == true

#new_record? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_cypher/relationship.rb', line 283

def new_record?  = @new_record

#persisted? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_cypher/relationship.rb', line 284

def persisted?   = !new_record? && internal_id.present?

#save(validate: true) ⇒ Object

Persistence API



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# File 'lib/active_cypher/relationship.rb', line 290

def save(validate: true)
  return false if validate && !valid?

  _run(:save) do
    if new_record?
      _run(:create) { create_relationship }
    else
      _run(:update) { update_relationship }
    end
  end
rescue ActiveCypher::RecordNotSaved, RuntimeError => e
  # Only catch specific validation errors, let other errors propagate
  if e.message.include?('must be persisted') || e.message.include?('creation returned no id')
    log_error "Failed to save #{self.class}: #{e.message}"
    false
  else
    raise
  end
end

#save! ⇒ Object

Bang version of save - raises exception if save fails For when you want your relationship persistence to be as dramatic as your code reviews



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# File 'lib/active_cypher/relationship.rb', line 312

def save!
  if save
    self
  else
    error_msgs = errors.full_messages.join(', ')
    error_msgs = 'Validation failed' if error_msgs.empty?
    raise ActiveCypher::RecordNotSaved,
          "#{self.class} could not be saved: #{error_msgs}. " \
          'Perhaps this relationship was never meant to be?'
  end
end