将方法代码移动到 Neo4j Cypher 查询

Question

我有一个 Spring Neo4j 存储库方法 getAvgVotesWeightForCriterion

@Query("MATCH (d:Decision)<-[:VOTED_FOR]-(v:Vote)-[:VOTED_ON]->(c:Criterion) WHERE id(d) = {0} AND id(c) = {1} RETURN avg(v.weight)")
double getAvgVotesWeightForCriterion(Decision decision, Criterion criterion);

而且我还有另一种方法 calculateWeight 完全用 Java 编写。此方法在循环内部使用 getAvgVotesWeightForCriterion

public double calculateWeight(Decision decision, List<Criterion> criteria) {
    double weight = 0;

    for (Criterion criterion : criteria) {
        weight += getAvgVotesWeightForCriterion(decision, criterion);
    }

    return weight;
}

是否可以将 calculateWeight 方法内的逻辑完全移动到 Cypher 查询？为了得到这样的东西：

@Query ....
double calculateWeight(Decision decision, List<Criterion> criteria)

Answer 1

这应该做你想做的事。

您按标准对 avg - 聚合进行分组，然后仅对权重求和。

MATCH (d:Decision)<-[:VOTED_FOR]-(v:Vote)-[:VOTED_ON]->(c:Criterion) 
WHERE id(d) = {0} AND id(c) IN {1} 
WITH c, avg(v.weight) as weight
RETURN sum(weight)

将方法代码移动到 Neo4j Cypher 查询

Move method code to Neo4j Cypher query

neo4j

graph-databases

cypher

spring-data-neo4j