4

I'm following a tutorial, and I'm using the last python2 (homebrew) with PyCharm (with project interpreter configured) - But I'm stuck in this part:

from py2neo import Graph, Node
graph = Graph()
nicole = Node("Person", name="Nicole")
graph.create(nicole)
graph.delete(nicole)
nicole = graph.merge_one("Person", "name", "Nicole")

Error:

Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
AttributeError: 'Graph' object has no attribute 'merge_one'

I already checked the documentation and it seems that I'm doing everything ok . I tried to uninstall and install last version of py2neo but with no success. How I solve this problem?

Expected behavior: Running that command from the python2 console: If that Person exists don't duplicate it but change its values, if don't exist create it.

Sebastián Palma
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bcloney
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  • I'm not sure, but from the documentation it says Neo4j has an _optional_ scheme database. so you may have to be using it for the `merge_one` method to exist. – martineau Dec 25 '18 at 23:14
  • I tried using `graph.schema.create_uniqueness_constraint("Person", "name")` , the command successful runs, but didn't solve the other _merge_one_ problem – bcloney Dec 25 '18 at 23:27

2 Answers2

3

I fastly ended up using the version 4 as opposed to 2. So using Graph.merge, solved the problem:

jonh = Node("Person", name="Jonh", age = 21)
graph.create(jonh)
ana = Node("Person", name="Ana", age = 44)
graph.create(ana)
michael = Node("Person", name="Ana", age = 33)
graph.merge(michael, "Person", "name") # So the age of Ana will change to 33, as expected.

For using the commands related to my question, the version 2 must be installed, for eg. directly from py2neo repo:

pip install https://github.com/technige/py2neo/archive/release/2.0.7.zip
Community
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bcloney
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1

From inspecting the source code, I think the function you're looking for is Graph.match_one. There is also a function Graph.merge, but that doesn't take Node as an argument.

littlebenlittle
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