python - 无法在Python中重现灯泡/py2neo来创建边缘(关系)

Question

我正在尝试使用 python 在 Neo4j 中顺序插入顶点和边。当我添加边时，现有节点不会被识别。无论我使用 py2neo 还是灯泡，我都会收到类似的错误消息。

请注意我正在使用:linux64 python 2.7灯泡0.3py2neo1.5neo4j-community1.8.2

带灯泡:

>>> from bulbs.neo4jserver import Graph
>>> g = Graph()
>>> g.vertices.create(name="James")
>>> g.vertices.create(name="Julie")
>>> g.edges.create(james, "knows", julie)

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-46-9ba24256218d> in <module>()
----> 1 g.edges.create(james, "knows", julie)

NameError: name 'james' is not defined

使用 py2neo

from py2neo import neo4j
graph=neo4j.GraphDatabaseService()
node=graph.create({"name":'James'},{'name':'Julie'})
rel=graph.create((james,"knows",julie))
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-8-591f826cfd05> in <module>()
      2 graph=neo4j.GraphDatabaseService()
      3 node=graph.create({"name":'James'},{'name':'Julie'})
----> 4 rel=graph.create((james,"knows",julie))

NameError: name 'james' is not defined

此外，如果我使用 rexster 而不是 neo4j，我也会遇到与 bulbs 相同的错误，即

>>> from bulbs.rexster import Graph
>>> g = Graph()
>>> g.vertices.create(name="James")
>>> g.vertices.create(name="Julie")
>>> g.edges.create(james, "knows", julie)
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-6-2cfb5faa42d1> in <module>()
      3 g.vertices.create(name="James")
      4 g.vertices.create(name="Julie")
----> 5 g.edges.create((james, "knows", julie))

NameError: name 'james' is not defined

这里出了什么问题？

谢谢

Answer 1

仅通过创建具有类似 name 属性的节点，不会自动创建应用程序变量 james 和 julie。您尚未分享任何 py2neo 代码，而且我对灯泡不熟悉，但在 py2neo 中您需要执行以下操作:

from py2neo import neo4j
graph_db = neo4j.GraphDatabaseService()
james, julie = graph_db.create(node(name="James"), node(name="Julie"))
graph_db.create(rel(james, "KNOWS", julie))

如果您愿意，您当然可以在同一个语句(和批处理)中创建节点和关系:

from py2neo import neo4j
graph_db = neo4j.GraphDatabaseService()
james, julie, friendship = graph_db.create(
    node(name="James"), node(name="Julie"), rel(0, "KNOWS", 1)
)