Class: Neo4j::Http::RelationshipClient

Inherits:
Object
  • Object
show all
Defined in:
lib/neo4j/http/relationship_client.rb

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(cypher_client) ⇒ RelationshipClient

Returns a new instance of RelationshipClient.



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# File 'lib/neo4j/http/relationship_client.rb', line 10

def initialize(cypher_client)
  @cypher_client = cypher_client
end

Class Method Details

.default ⇒ Object 



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# File 'lib/neo4j/http/relationship_client.rb', line 6

def self.default
  @default ||= new(CypherClient.default)
end

Instance Method Details

#build_match_selector(name, data) ⇒ Object 



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# File 'lib/neo4j/http/relationship_client.rb', line 69

def build_match_selector(name, data)
  selector = +"#{name}:#{data.label}"
  selector << " {#{data.key_name}: $#{name}.#{data.key_name}}" if data.key_name.present?
  selector
end

#delete_relationship(relationship:, from:, to:) ⇒ Object 



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# File 'lib/neo4j/http/relationship_client.rb', line 75

def delete_relationship(relationship:, from:, to:)
  from_selector = build_match_selector(:from, from)
  to_selector = build_match_selector(:to, to)
  relationship_selector = build_match_selector(:relationship, relationship)

  cypher = <<-CYPHER
    MATCH (#{from_selector}) - [#{relationship_selector}] - (#{to_selector})
    WITH from, to, relationship
    DELETE relationship
    RETURN from, to
  CYPHER

  results = @cypher_client.execute_cypher(cypher, from: from, to: to)
  results&.first
end

#delete_relationship_on_primary_key(relationship:) ⇒ Object 



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# File 'lib/neo4j/http/relationship_client.rb', line 91

def delete_relationship_on_primary_key(relationship:)
  # protection against mass deletion of relationships
  return if relationship.key_name.nil?

  relationship_selector = build_match_selector(:relationship, relationship)

  cypher = <<-CYPHER
    MATCH () - [#{relationship_selector}] - ()
    WITH relationship
    DELETE relationship
    RETURN relationship
  CYPHER

  results = @cypher_client.execute_cypher(cypher, relationship: relationship)
  results&.first
end

#find_relationship(from:, relationship:, to:) ⇒ Object 



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# File 'lib/neo4j/http/relationship_client.rb', line 64

def find_relationship(from:, relationship:, to:)
  results = find_relationships(from: from, to: to, relationship: relationship)
  results&.first
end

#find_relationships(from:, relationship:, to:) ⇒ Object 



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# File 'lib/neo4j/http/relationship_client.rb', line 46

def find_relationships(from:, relationship:, to:)
  from_match_clause = build_match_selector(:from, from)
  to_match_clause = build_match_selector(:to, to)
  relationship_clause = build_match_selector(:relationship, relationship)
  cypher = <<-CYPHER
    MATCH (#{from_match_clause}) - [#{relationship_clause}] - (#{to_match_clause})
    RETURN from, to, relationship
  CYPHER

  @cypher_client.execute_cypher(
    cypher,
    from: from,
    to: to,
    relationship: relationship,
    access_mode: "READ"
  )
end

#upsert_relationship(relationship:, from:, to:, create_nodes: false) ⇒ Object 



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# File 'lib/neo4j/http/relationship_client.rb', line 14

def upsert_relationship(relationship:, from:, to:, create_nodes: false)
  match_or_merge = create_nodes ? "MERGE" : "MATCH"
  from_selector = build_match_selector(:from, from)
  to_selector = build_match_selector(:to, to)
  relationship_selector = build_match_selector(:relationship, relationship)

  on_match = ""
  if relationship.attributes.present?
    on_match = <<-CYPHER
      ON CREATE SET relationship += $relationship_attributes
      ON MATCH SET relationship += $relationship_attributes
    CYPHER
  end

  cypher = +<<-CYPHER
    #{match_or_merge} (#{from_selector})
    #{match_or_merge} (#{to_selector})
    MERGE (from) - [#{relationship_selector}] - (to)
    #{on_match}
    RETURN from, to, relationship
  CYPHER

  results = @cypher_client.execute_cypher(
    cypher,
    from: from,
    to: to,
    relationship: relationship,
    relationship_attributes: relationship.attributes
  )
  results&.first
end