apoc.nodes.cycles
Procedure APOC Core
CALL apoc.nodes.cycles([nodes], $config) - Detect all path cycles from node list
Config parameters
| name | type | default | description |
|---|---|---|---|
maxDepth |
long |
Integer.MAX_VALUE |
The max number of hops (relationships) to search for cycles. |
relTypes |
List<String> |
[] |
The relationship types to detect cycles. By default, all types will be considered. |
Usage Examples
The examples in this section are based on the following sample graph:
CREATE (m1:Start {bar: 'alpha'}) with m1 CREATE (m1)-[:DEPENDS_ON {id: 0}]->(m2:Module {bar: 'one'})-[:DEPENDS_ON {id: 1}]->(m3:Module {bar: 'two'})-[:DEPENDS_ON {id: 2}]->(m1) WITH m1, m2, m3 CREATE (m1)-[:DEPENDS_ON {id: 3}]->(m2), (m2)-[:ANOTHER {id: 4}]->(m3), (m2)-[:DEPENDS_ON {id: 5}]->(m3) CREATE (m1)-[:DEPENDS_ON {id: 6}]->(:Module {bar: 'seven'})-[:DEPENDS_ON {id: 7}]->(:Module {bar: 'eight'})-[:DEPENDS_ON {id: 8}]->(m1);
CREATE (m1:Start {bar: 'beta'}) with m1 CREATE (m1)-[:MY_REL {id: 9}]->(m2:Module {bar: 'three'})-[:MY_REL {id: 10}]->(m3:Module {bar: 'four'})-[:MY_REL {id: 11}]->(m1);
CREATE (m1:Start {bar: 'gamma'}) with m1 CREATE (m1)-[:DEPENDS_ON {id: 12}]->(m2:Module {bar: 'five'})-[:DEPENDS_ON {id: 13}]->(m3:Module {bar: 'six'});
CREATE (m1:Start {bar: 'delta'}) with m1 CREATE (m1)-[:DEPENDS_ON {id: 20}]->(m1);
CREATE (m1:Start {bar: 'epsilon'}) with m1 CREATE (m1)-[:DEPTH_ONE {id: 30}]->(:Module {bar: 'seven'})-[:DEPTH_ONE {id: 31}]->(m1);The data set above consists in a node alpha with 2 cycles, a node beta with 1 cycles,
a gamma node without cycles, a node delta with 1 cycle (with only 1 intermediate node),
and a epsilon node with a self-relationship:
We can execute the following query which looks for all the cycles starting from the Start nodes:
MATCH (m1:Start) WITH collect(m1) as nodes CALL apoc.nodes.cycles(nodes) YIELD path RETURN path
Note that, in case of nodes with double-rels
(in this example, between (:Start {bar: 'alpha'}) and (:Module {bar: 'one'}) and between (:Module {bar: 'one'}) and (:Module {bar: 'two'})),
only the first cycle found will be considered.
We can also specify a list of relationship types to detect cycles. For example:
MATCH (m1:Start) WITH collect(m1) as nodes CALL apoc.nodes.cycles(nodes, {relTypes: ["DEPENDS_ON", "MY_REL", "NOT_EXISTENT"]}) YIELD path RETURN path
Furthermore, we can specify a maxDepth to consider cycles with only n intermediate nodes. For example:
MATCH (m1:Start) WITH collect(m1) as nodes CALL apoc.nodes.cycles(nodes, {maxDepth: 1}) YIELD path RETURN path
Note that is allowed also a maxDepth: 0, returning only nodes with one or more self relationships:
MATCH (m1:Start) WITH collect(m1) as nodes CALL apoc.nodes.cycles(nodes, {relTypes: ['DEPENDS_ON'], maxDepth: 0}) YIELD path RETURN path