Question

我有一个嵌套的has_many关系，我试图将其映射到json结果。

博客中的以下示例显示了我想要做的事情，除了它没有嵌套

 MATCH (a:Person { name: "Andres" })-[:FATHER_OF]->(child)
  RETURN 
  {name:a.name, kids:collect(child.name)} as document

我想要的是这样的东西

 MATCH (a:Person { name: "Andres" })-[:FATHER_OF]->(child)-[:has_read]->(book)-[:has_chapter]->(chapter)
  RETURN 
  {name:a.name, kids:collect({"name":child.name, has_read:collect(book)})} as document

在这种情况下，我想返回一个像这样结构的json对象：

{
  "name": "Andres"
  "kids": [
           {
             "name":"Bob"
             "has_read": [
                           {
                            "name":"Lord of the Rings",
                            "chapters": ["chapter1","chapter2","chapter3"]
                           },
                           {
                            "name":"The Hobbit",
                            "chapters": ["An unexpected party","Roast mutton"]
                           }
                         ]
           },
           {
             "name":"George"
             "has_read": [
                           {
                            "name":"Lord of the Rings",
                            "chapters": ["chapter1","chapter2","chapter3"]
                           },
                           {
                            "name":"Silmarillion",
                            "chapters": ["chapter1","chapter2"]
                           }
                         ]
           }

          ]
}

Answer 1

你可以尝试：

如果你保持匹配到章节，你将需要明确 collect(distinct book.title)否则不会。

MATCH (a:Person { name: "Andres" })-[:FATHER_OF]->(child),
      (child)-[:has_read]->(book)-[:has_chapter]->(chapter)
WITH a,child,collect(distinct book.title) as books
RETURN 
  {name:a.name, 
   kids:collect({name:child.name, 
                 has_read:books})} as document

哦，如果你想在结果中包含章节，那么只需添加另一个：）

MATCH (a:Person { name: "Andres" })-[:FATHER_OF]->(child),
      (child)-[:has_read]->(book)-[:has_chapter]->(chapter)
WITH a,child, {title: book.title, chapters: collect(chapter.title)} as book_doc
WITH a,child, collect(book_doc) as books
RETURN 
  {name:a.name, 
   kids:collect({name:child.name, 
                 has_read:books})} as document

请参阅： http://console.neo4j.org/r/kua2pi

cypher中嵌套的has_many关系

1 个答案: