java – 当同一节点有很多关系时,Neo4jRepository @Query结果错误

2019年7月20日 538次阅读

我们假设我们使用这个简单的图模型：

@NodeEntity
class Ad {    
    // GraphId and more Ad attributes...

    @Relationship(type = "HAS_ADVERTISER", direction = Relationship.OUTGOING)
    private User advertiser;

    @Relationship(type = "IS_FAVOURITE_TO", direction = Relationship.OUTGOING)
    private Set<User> favourites = new HashSet<>();

    // Getters and setters
 }

编辑：按照其中一个aswers的建议,我尝试将传入的关系添加到用户实体,但问题仍然存在.

@NodeEntity
class User {
    // User attributes. No incoming relationships for HAS_ADVERTISER neither IS_FAVOURITE_TO...

   // EDIT: Added incoming relationships to User entity, but the problem still remains. Tried annotating getters/setters, but neither works
   @Relationship(type = "HAS_ADVERTISER", direction = Relationship.INCOMING)
   private Set<Ad> ads = new HashSet<>();

   @Relationship(type = "IS_FAVOURITE_TO", direction = Relationship.INCOMING)
   private Set<Ad> favourites = new HashSet<>();

   @Relationship(direction = Relationship.INCOMING)
   public Set<Ad> getAds() {
       return ads;
   }

   @Relationship(direction = Relationship.INCOMING)
   public void setAds(Set<Ad> ads) {
       this.ads = ads;
   }

   @Relationship(direction = Relationship.INCOMING)
   public Set<Ad> getFavourites() {
       return favourites;
   }

   @Relationship(direction = Relationship.INCOMING)
   public void setFavourites(Set<Ad> favourites) {
       this.favourites = favourites;
   }
}

如果我通过neo4j控制台执行密码查询以检索包含广告客户和收藏夹信息的广告,那么它运行良好：

MATCH (ad:Ad),
(ad)-[has_advertiser:HAS_ADVERTISER]->(advertiser:User),
(ad)-[is_favourite_to: IS_FAVOURITE_TO] -> (favouriteUser:User)
return ad, has_advertiser, advertiser, is_favourite_to, favouriteUser

《java – 当同一节点有很多关系时,Neo4jRepository @Query结果错误》

但是,如果我通过neo4jRepository执行查询：

>广告客户用户已正确保留.
>收藏夹集中有两个用户：广告客户用户总是被添加到集合中,这是不正确的,因为与该用户没有IS_FAVOURITE_TO关系.

@Repository
public interface AdRepository extends Neo4jRepository<Ad> {

    @Query("MATCH (ad:Ad)," +
            "(ad)-[has_advertiser:HAS_ADVERTISER]->(advertiser:User)," +
            "(ad)-[is_favourite_to: IS_FAVOURITE_TO] -> (favouriteUser:User)" +
            "return ad, has_advertiser, advertiser, " +
            "is_favourite_to, favouriteUser ")
    List<Ad> findAds();
 }

《java – 当同一节点有很多关系时,Neo4jRepository @Query结果错误》

我可以在查询或图形模型中更改某些内容以避免这种情况吗？
也许是spring-data-neo4j的bug？

版本：

<spring-data-neo4j.version>4.2.0.M1</spring-data-neo4j.version>
<neo4j.ogm.version>2.0.5</neo4j.ogm.version>

最佳答案 这是因为OGM认为这是一个模糊的模型.如果您将传入关系添加到用户,则应解决您的问题.

更新：经过进一步调查,这确实是一个错误.开业https://github.com/neo4j/neo4j-ogm/issues/276

解决方法是在广告和用户中注释所有getter和setter(并确保@Relationship注释包含关系类型和方向).

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