Imagine a user being part of different groups.
A group can have different roles, and a user can be part of different groups.
He also can have different roles in different groups apart from the membership.
The association of a User, a Group and a Role can be referred to as a HyperEdge.
However, it can be easily modeled in a property graph as a node that captures this n-ary relationship, as depicted below in the U1G2R1
node.
To find out in what roles a user is for a particular groups (here Group2), the following query can traverse this HyperEdge node and provide answers.
Query.
START n=node:node_auto_index(name = 'User1') MATCH n-[:hasRoleInGroup]->hyperEdge-[:hasGroup]->group, hyperEdge-[:hasRole]->role WHERE group.name = "Group2" RETURN role.name
The role of User1
is returned:
Here, find all groups and the roles a user has, sorted by the name of the role.
Query.
START n=node:node_auto_index(name = "User1") MATCH n-[:hasRoleInGroup]->hyperEdge-[:hasGroup]->group, hyperEdge-[:hasRole]->role RETURN role.name, group.name ORDER BY role.name asc
The groups and roles of User1
are returned:
Assume a more complicated graph:
User1
, User2
.
User1
is in Group1
, Group2
, Group3
.
User1
has Role1
, Role2
in Group1
; Role2
, Role3
in Group2
; Role3
, Role4
in Group3
(hyper edges).
User2
is in Group1
, Group2
, Group3
.
User2
has Role2
, Role5
in Group1
; Role3
, Role4
in Group2
; Role5
, Role6
in Group3
(hyper edges).
The graph for this looks like the following (nodes like U1G2R23
representing the HyperEdges):
To return Group1
and Group2
as User1
and User2
share at least one common role in these two groups, the query looks like this:
Query.
START u1=node:node_auto_index(name = 'User1'), u2=node:node_auto_index(name = 'User2') MATCH u1-[:hasRoleInGroup]->hyperEdge1-[:hasGroup]->group, hyperEdge1-[:hasRole]->role, u2-[:hasRoleInGroup]->hyperEdge2-[:hasGroup]->group, hyperEdge2-[:hasRole]->role RETURN group.name, count(role) ORDER BY group.name ASC
The groups where User1
and User2
share at least one common role:
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