6.12. Pretty graphs

This section is showing how to create some of the named pretty graphs on Wikipedia.

Star graph

The graph is created by first creating a center node, and then once per element in the range, creates a leaf node and connects it to the center.

Parameters 

{ }

Query 

CREATE (center)
FOREACH (x IN range(1,6)| CREATE (leaf),(center)-[:X]->(leaf))
RETURN id(center) AS id;

The query returns the id of the center node.

Result

id
1 row
Nodes created: 7
Relationships created: 6

0

Figure 6.11. Graph

Wheel graph

This graph is created in a number of steps:

  • Create a center node.
  • Once per element in the range, create a leaf and connect it to the center.
  • Connect neighboring leafs.
  • Find the minimum and maximum leaf and connect these.
  • Return the id of the center node.

Parameters 

{ }

Query 

CREATE (center)
FOREACH (x IN range(1,6)| CREATE (leaf { count:x }),(center)-[:X]->(leaf))
WITH center
MATCH (large_leaf)<--(center)-->(small_leaf)
WHERE large_leaf.count = small_leaf.count + 1
CREATE (small_leaf)-[:X]->(large_leaf)
WITH center, min(small_leaf.count) AS min, max(large_leaf.count) AS max
MATCH (first_leaf)<--(center)-->(last_leaf)
WHERE first_leaf.count = min AND last_leaf.count = max
CREATE (last_leaf)-[:X]->(first_leaf)
RETURN id(center) AS id

The query returns the id of the center node.

Result

id
1 row
Nodes created: 7
Relationships created: 12
Properties set: 6

0

Figure 6.12. Graph

Complete graph

To create this graph, we first create 6 nodes and label them with the Leaf label. We then match all the unique pairs of nodes, and create a relationship between them.

Parameters 

{ }

Query 

FOREACH (x IN range(1,6)| CREATE (leaf:Leaf { count : x }))
WITH *
MATCH (leaf1:Leaf),(leaf2:Leaf)
WHERE id(leaf1)< id(leaf2)
CREATE (leaf1)-[:X]->(leaf2);

Nothing is returned by this query.

Result

Nodes created: 6
Relationships created: 15
Properties set: 6
Labels added: 6

(empty result)

Figure 6.13. Graph

Friendship graph

This query first creates a center node, and then once per element in the range, creates a cycle graph and connects it to the center

Parameters 

{ }

Query 

CREATE (center)
FOREACH (x IN range(1,3)| CREATE (leaf1),(leaf2),(center)-[:X]->(leaf1),(center)-[:X]->(leaf2),
  (leaf1)-[:X]->(leaf2))
RETURN ID(center) AS id

The id of the center node is returned by the query.

Result

id
1 row
Nodes created: 7
Relationships created: 9

0

Figure 6.14. Graph