Cypher：如何导航图以找到正确的路径(Cypher: how to navigate graph to find the right path)

Cypher：如何导航图以找到正确的路径(Cypher: how to navigate graph to find the right path)

我是Cypher的新手，我正在努力学习如何正确导航图形。 我有这样的情况：2用户已经关联了相同的服务，该服务可以通过帐户访问。 因此，用户'usr01'可以通过账户'acct01'访问服务'srv01'; 用户'usr02可以使用账户'acct02'访问服务'srv01'。 目标是提取2个这样的记录：

usr01 - srv01 - acct01 usr02 - srv01 - acct02

所以，我执行了这些查询：

创建节点：

create (s:XService {serviceId:'srv01'}) return s; create (u:XUser {userId:'usr01'}) return u; create (u:XUser {userId:'usr02'}) return u; create (u:XAccount {accountId:'acct01'}) return u; create (u:XAccount {accountId:'acct02'}) return u;

建立关系：

MATCH (u:XUser{userId:'usr01'}), (s:XService {serviceId:'srv01'}), (a:XAccount {accountId:'acct01'}) CREATE (u)-[:HAS_SERVICE]->(s)-[:HAS_ACCOUNT]->(a) MATCH (u:XUser{userId:'usr02'}), (s:XService {serviceId:'srv01'}), (a:XAccount {accountId:'acct02'}) CREATE (u)-[:HAS_SERVICE]->(s)-[:HAS_ACCOUNT]->(a)

我收到的图表结果是这样的

如果我执行这个查询 - 从用户usr01开始：

MATCH (u:XUser {userId: 'usr01'}) OPTIONAL MATCH (u)-[:HAS_SERVICE]->(s:XService) OPTIONAL MATCH (s)-[:HAS_ACCOUNT]->(a:XAccount)

返回u.userId，s.serviceId，a.accountId;

我得到这个结果：

那么，我如何才能获得上述结果（usr01 - srv01 - acct01），而不是我收到的笛卡尔产品？ 提前致谢

I'm new to Cypher, I'm trying to learn to navigate a graph correctly. I hava a situation like this: 2 Users have associated the same Service, the service is accessible via an Account. So, the user 'usr01' can access to the Service 'srv01' with account 'acct01'; the user 'usr02 can access to the Service 'srv01' with account 'acct02'. The aim is to extract 2 records like this:

usr01 - srv01 - acct01 usr02 - srv01 - acct02

So, I executed these queries:

Creation of nodes:

create (s:XService {serviceId:'srv01'}) return s; create (u:XUser {userId:'usr01'}) return u; create (u:XUser {userId:'usr02'}) return u; create (u:XAccount {accountId:'acct01'}) return u; create (u:XAccount {accountId:'acct02'}) return u;

Relationship creation:

MATCH (u:XUser{userId:'usr01'}), (s:XService {serviceId:'srv01'}), (a:XAccount {accountId:'acct01'}) CREATE (u)-[:HAS_SERVICE]->(s)-[:HAS_ACCOUNT]->(a) MATCH (u:XUser{userId:'usr02'}), (s:XService {serviceId:'srv01'}), (a:XAccount {accountId:'acct02'}) CREATE (u)-[:HAS_SERVICE]->(s)-[:HAS_ACCOUNT]->(a)

The graph result I've received is this

If I execute this query - starting from the user usr01:

MATCH (u:XUser {userId: 'usr01'}) OPTIONAL MATCH (u)-[:HAS_SERVICE]->(s:XService) OPTIONAL MATCH (s)-[:HAS_ACCOUNT]->(a:XAccount)

RETURN u.userId, s.serviceId, a.accountId;

I obtain this result:

So, how can I do to obtain the result described above (usr01 - srv01 - acct01) and not the cartesian product that I've received? Thanks in advance

最满意答案

问题是，当您添加服务和帐户之间的关系时，您不指示与用户的关联关系。 作为解决方案，您可以创建一个智能节点“访问规则”：

MERGE (s:XService {serviceId:'srv01'}) MERGE (u1:XUser {userId:'usr01'}) MERGE (ua1:XAccount {accountId:'acct01'}) MERGE (u1)-[:can_access]->(ca1:AccessRule)-[:to_service]->(s) MERGE (ca1)-[:with_account]->(ua1) MERGE (u2:XUser {userId:'usr02'}) MERGE (ua2:XAccount {accountId:'acct02'}) MERGE (u2)-[:can_access]->(ca2:AccessRule)-[:to_service]->(s) MERGE (ca2)-[:with_account]->(ua2)

和一个查询：

MATCH (u:XUser {userId: 'usr01'}) OPTIONAL MATCH ps = (u)-[:can_access]->(ca1:AccessRule)-[:to_service]->(s:XService) OPTIONAL MATCH pa = (ca1)-[:with_account]->(a:XAccount) RETURN u, ps, pa

The problem is that when you add the relationship between the service and the account you do not indicate an association relationship with the user. As a solution, you can make a smart node "Access Rule":

MERGE (s:XService {serviceId:'srv01'}) MERGE (u1:XUser {userId:'usr01'}) MERGE (ua1:XAccount {accountId:'acct01'}) MERGE (u1)-[:can_access]->(ca1:AccessRule)-[:to_service]->(s) MERGE (ca1)-[:with_account]->(ua1) MERGE (u2:XUser {userId:'usr02'}) MERGE (ua2:XAccount {accountId:'acct02'}) MERGE (u2)-[:can_access]->(ca2:AccessRule)-[:to_service]->(s) MERGE (ca2)-[:with_account]->(ua2)

And a query:

MATCH (u:XUser {userId: 'usr01'}) OPTIONAL MATCH ps = (u)-[:can_access]->(ca1:AccessRule)-[:to_service]->(s:XService) OPTIONAL MATCH pa = (ca1)-[:with_account]->(a:XAccount) RETURN u, ps, pa