Neo4j Cypher 删除查询

Question

我对@9​​87654321@ 实体删除有以下 Neo4j Cypher 查询：

MATCH (d:Decision) 
WHERE id(d) IN {decisionsIds} 
OPTIONAL MATCH (d)-[r]-(t) 
DELETE d, r WITH t, r 
WHERE NOT (id(t) IN {decisionsIds}) 
OPTIONAL MATCH (t)-[r2:VOTED_ON|:CREATED_BY|:VOTED_FOR]-() 
WHERE r2 <> r WITH t, r2 
WHERE none(x in labels(t) WHERE x in ['User', 'Decision']) DELETE t, r2

以前我有一个Vote 实体，它与VOTED_ON 和VOTED_FOR 与实体Criterion 和Decision 有关系。此外，Vote 与 CREATED_BY 有关系 User 实体。

一切正常。

今天，我更改了此架构。我引入了新的VoteGroup 实体。 现在，VoteGroup 而不是 Vote 包含 VOTED_ON 和 VOTED_FOR 与实体 Criterion 和 Decision 的关系：

@NodeEntity
public class VoteGroup extends BaseEntity {

    private static final String VOTED_ON = "VOTED_ON";
    private final static String VOTED_FOR = "VOTED_FOR";
    private final static String CONTAINS = "CONTAINS";

    @GraphId
    private Long id;

    @RelatedTo(type = VOTED_FOR, direction = Direction.OUTGOING)
    private Decision decision;

    @RelatedTo(type = VOTED_ON, direction = Direction.OUTGOING)
    private Criterion criterion;

    @RelatedTo(type = CONTAINS, direction = Direction.OUTGOING)
    private Set<Vote> votes = new HashSet<>();

    private double avgVotesWeight;

    private long totalVotesCount;

.....

}

Vote 实体现在看起来像：

@NodeEntity
public class Vote extends BaseEntity {

    private final static String CONTAINS = "CONTAINS";
    private final static String CREATED_BY = "CREATED_BY";

    @GraphId
    private Long id;

    @RelatedTo(type = CONTAINS, direction = Direction.INCOMING)
    private VoteGroup group;

    @RelatedTo(type = CREATED_BY, direction = Direction.OUTGOING)
    private User author;

    private double weight;

....
}

请帮助我更改提到的 Cypher 查询以删除 Votes。在我的架构更改后，它现在会删除 VoteGroups（没关系），但不会删除 Votes。我还需要删除Votes 以及Votes 和User 之间的关系。

更新

下面的新查询现在可以工作了（至少我所有的测试都通过了）：

MATCH (d:Decision) 
WHERE id(d) IN {decisionsIds} 
OPTIONAL MATCH (d)-[r]-(t) 
DELETE d, r 
WITH t, r 
WHERE NOT (id(t) IN {decisionsIds}) 
OPTIONAL MATCH (t)-[r2:VOTED_ON|:CREATED_BY|:VOTED_FOR]-()-[r3:CONTAINS]-(t2) 
WHERE r2 <> r 
WITH t, r2, t2, r3 
WHERE none(x in labels(t) 
WHERE x in ['User', 'Decision']) 
DELETE t, r2, t2, r3

但我仍然不确定这个查询是否 100% 正确...无论如何，我将添加一堆测试以检查所有内容。

您能否也验证此查询？ 尤其是我不确定删除了所有关系并没有在数据库中留下垃圾。

Answer 1

看起来很复杂。

你不能只指定路径并删除整个路径吗？

MATCH (d:Decision) WHERE id(d) IN {decisionsIds} 
OPTIONAL MATCH path = (d)-[r1:VOTED_ON|:CREATED_BY|:VOTED_FOR]->(t)<-[r2:VOTED_ON|:CREATED_BY|:VOTED_FOR]-()
DELETE path

// or 
DELETE d,t,r1,r2