在Cypher查询中允许深度参数 [英] Allow parameters for depth in Cypher query

问题描述

我正在使用用于Python的Neo4j Bolt驱动程序1.7 来提取特定数据库的路径，这是导致问题的代码示例.

I'm using Neo4j Bolt Driver 1.7 for Python to extract paths from a specific database, here's a sample of code that causes the problem.

from neo4j import GraphDatabase

uri = "bolt://0.0.0.0:7878"
driver = GraphDatabase.driver(uri, auth=("neo4j", "neo4j"))

db = driver.session()
query =  '''
    MATCH tree = (n:Class)-[r:SUBCLASSOF*{depth}]->(parent)      # <---- ERROR here
    WHERE n.obo_id = {go}
    RETURN [n in nodes(tree) | n.obo_id] as GOID
'''
results = []
goid = "GO:0051838"
for record in db.run(query, go=goid, depth="..2"):
    results.append(record["GOID"])

print(results)

当我使用{depth}参数时，出现以下错误:

When I use {depth} parameter I get the following error:

Traceback (most recent call last):
  File "neoEnrich.py", line 16, in <module>
    for record in db.run(query, go=goid, depth="..2"):
  File "/usr/local/lib/python3.6/site-packages/neo4j/__init__.py", line 499, in run
    self._connection.fetch()
  File "/usr/local/lib/python3.6/site-packages/neobolt/direct.py", line 414, in fetch
    return self._fetch()
  File "/usr/local/lib/python3.6/site-packages/neobolt/direct.py", line 454, in _fetch
    response.on_failure(summary_metadata or {})
  File "/usr/local/lib/python3.6/site-packages/neobolt/direct.py", line 738, in on_failure
    raise CypherError.hydrate(**metadata)
neobolt.exceptions.CypherSyntaxError: Parameter maps cannot be used in MATCH patterns (use a literal map instead, eg. "{id: {param}.id}") (line 2, column 38 (offset: 42))
"    MATCH tree = (n:Class)-[r:SUBCLASSOF*{depth}]->(parent)"
                                          ^

当用..2替换{depth}时，我得到了预期的结果:

when replacing {depth} by ..2, I got the desired result:

[['GO:0051838', 'GO:0051801'],
 ['GO:0051838', 'GO:0051801', 'GO:0051883'],
 ['GO:0051838', 'GO:0051801', 'GO:0051715'],
 ['GO:0051838', 'GO:0051873'],
 ['GO:0051838', 'GO:0051873', 'GO:0051883'],
 ['GO:0051838', 'GO:0051873', 'GO:0051852']]

这里是否有允许深度参数的方法?由于用户将指定深度(将是功能参数).

Is there a way to allow parameters for depth here ? Since a user will specify the depth (will be a function parameter).

推荐答案

不允许使用参数设置节点标签，关系标签，关系深度.

Parameters are not allowed to set Node Labels, Relationship Labels, Relationship depths.

如果您确实需要此深度作为参数，请在python中将查询创建为字符串，并将关系深度作为参数传递给它.

If you really need this depth as a parameter then create a query as a string in python and pass relationship depths to it as a parameter.

保留查询中的其他参数(此处为go).

Keep other parameters(here go) as it is in the query.

这篇关于在Cypher查询中允许深度参数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！