Question

我刚开始学习py2neo和neo4j，我遇到了重复这个问题。我在python中编写了一个简单的python脚本，它将创建一个科学论文和作者的数据库。我只需要添加论文和作者的节点并添加他们的关系。我正在使用这段代码，它工作正常，但速度很慢：

    paper = Node('Paper', id=post_id)
    graph.merge(paper)
    paper['created_time'] = created_time
    graph.push(paper)

    for author_id,author_name in paper_dict['authors']:
        researcher = Node('Person', id=author_id)
        graph.merge(researcher)
        researcher['name'] = author_name
        graph.push(researcher)

        wrote = Relationship(researcher,'author', paper)
        graph.merge(wrote)

因此，为了同时编写多个关系，我尝试使用事务。我的问题是，如果我为同一篇论文和作者多次运行，它会假定它们是不同的实体，然后复制数据库中的每个节点和关系（我试图多次运行该脚本）。但是之前的代码并没有发生同样的情况。这是使用事务的代码：

    tx = graph.begin()

    paper = Node('Paper', id=post_id)
    paper['created_time'] = created_time

    tx.create(paper)

    for author_id,author_name in paper_dict['authors']:
        researcher = Node('Person', id=author_id)
        researcher['name'] = author_name
        tx.create(researcher)
        wrote = Relationship(researcher,'author', paper)
        tx.create(wrote)
    tx.commit()

Answer 1

我相信你应该使用merge函数，而不是create函数来避免重复。请考虑以下源代码：

    import py2neo

    from py2neo import Graph, Node, Relationship

    def authenticateAndConnect():
      py2neo.authenticate('localhost:7474', 'user', 'password')
      return Graph('http://localhost:7474/default.graphdb/data/')     

    def actorsDictionary():
      return 

    def createData():
      graph = authenticateAndConnect()
      tx = graph.begin()
      movie = Node('Movie', title='Answer')

      personDictionary = [{'name':'Dan', 'born':2001}, {'name':'Brown', 'born':2001}]
      for i in range(10):
        for person in personDictionary:
          person = Node('Person', name=person['name'], born=person['born'])
          tx.merge(person)
          actedIn = Relationship(person, 'ACTED_IN', movie)
          tx.merge(actedIn)

      tx.commit()

    if __name__ == '__main__':
      for i in range(10):
          createData()

py2neo事务提交重复

1 个答案: