如何使用稀疏属性上的WHERE子句来密码查询neo4j DB [英] How to cypher query a neo4j DB with WHERE clause on sparse property

问题描述

我的Neo4j数据库中有一些节点，这些节点具有并非在所有节点上都存在的某些属性，但是我想使用带有WHERE子句的Cypher查询这些属性.

I have Nodes in my Neo4j database that have certain properties that do not exist on all nodes, but I want to query against those properties with Cypher with a WHERE clause.

示例数据:

{id:"52", name:"Jim", age:"32", gender:"M"}
{id:"55", name:"Lisa", age:"22", gender:"F"}
{id:"97", name:"Chris", age:"38"}

现在，如果我想对性别运行Cypher查询，它将在Chris记录上给我一个错误，指出该节点上不存在性别属性.

Now, if I want to run a Cypher query on gender, it gives me an error on the Chris record, stating that the gender property does not exist on that node.

Cypher查询示例:

Example Cypher query:

START n=NODE(*) WHERE n.gender="M" RETURN n;

我收到的具体错误消息是:

The specific error message I am getting is:

EntityNotFoundException: The property 'gender' does not exist on Node[4925]

我正在运行Neo4j的1.9.2版本.我想升级到2.x并尝试使用gallery和auto_indexes.但是，我还不能离开稳定版本.

I am running version 1.9.2 of Neo4j. I'd like to upgrade to 2.x and try to use labels and auto_indexes galore. But, I'm not in a position go move away from the stable release yet.

有什么方法可以通过Cypher查询或1.9.2索引功能解决此问题?

Any way to solve this with Cypher query, or with 1.9.2 indexing features?

推荐答案

您可以这样做:

WHERE n.gender! = "M"

或

WHERE has(n.gender) AND n.gender = "M"

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