Question

我想根据从json文件读取的数据创建Neo4j图，但是我无法循环获得的数据。

我试图按照以下示例进行操作： https://neo4j.com/blog/cypher-load-json-from-url/

但是，我的apoc.load.json结果的结构似乎并不相似。我试图弄清楚我可以代替什么：

UNWIND data.items as q

在示例中，对于我来说，这是行不通的。

要了解输出的结构，我在Neo4j浏览器中执行了此操作：

CALL apoc.load.json('mytest.json') YIELD value
RETURN keys(value)

结果：

["favorites", "sentiment", "content-length", "keywords", "published-at", "reach", "title", "facts", "posts", "normalized-flesch-score", "ext-url", "shares", "last-modified", "score", "xscore", "companies", "quote", "provider", "content-type", "created-at", "categories", "id", "lang", "value", "keyphrases", "annotation", "duplicates", "karma", "topics", "subjects", "al", "possibly-sensitive", "inserted-at", "tags", "replies", "entities", "meta", "domain", "flesch-score", "locations", "parent-id", "relations", "adult", "non-media-entities", "user", "tr", "status"]
["favorites", "sentiment", "content-length", "keywords", "published-at", "reach", "title", "facts", "posts", "normalized-flesch-score", "ext-url", "shares", "last-modified", "score", "xscore", "companies", "quote", "provider", "content-type", "created-at", "categories", "id", "lang", "value", "keyphrases", "annotation", "duplicates", "karma", "topics", "subjects", "al", "possibly-sensitive", "inserted-at", "tags", "replies", "entities", "meta", "domain", "flesch-score", "locations", "parent-id", "relations", "adult", "non-media-entities", "user", "tr", "status"]
...

但是，当我尝试遍历输出中的对象并返回这样的一个键时：

CALL apoc.load.json('mytest.json') YIELD value
UNWIND value AS v
RETURN v.favorites

我得到一个错误：

Neo.ClientError.Statement.SyntaxError: Type mismatch: expected List<T> but was Map (line 2, column 8 (offset: 62))

     "UNWIND value AS v"
             ^

另一方面，如果我遍历实例value.title而不是value，则会得到有意义的值。

然后，我看了一些用cypher循环遍历地图的示例，但这些地图显示那里的结构都不同，并且解决方案（至少对于初学者而言）不适用于我的问题。

如果有人可以给我一些有关如何遍历我所拥有的对象的信息，那将是很好的。提前非常感谢！

Answer 1

您无需在此处使用unwind。您可以简单地将收藏夹返回为：

CALL apoc.load.json('mytest.json') YIELD value
RETURN value.favorites

Answer 2

original_state返回的每个updated_orders都是map，而不是列表。

要从地图上获取任何属性（例如value）的值，只需使用apoc.load.json（或foo）。例如：

value.foo

Neo4j：在Cypher

2 个答案: