Prev |  | Next

## 7.14. Pretty graphs

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

### 7.14.1. 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.

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 ms
`8`

Figure 7.12. Graph

### 7.14.2. 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.
- Select 2 leafs from the center node and connect them.
- Find the minimum and maximum leaf and connect these.
- Return the id of the center node.

Query.

    CREATE center
    foreach( x in range(1,6) :

    CREATE leaf={count:x}, center-[:X]->leaf
    )
    ==== center ====
    MATCH large_leaf<--center-->small_leaf
    WHERE large_leaf.count = small_leaf.count + 1
    CREATE small_leaf-[:X]->large_leaf

    ==== 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 ms
`8`

Figure 7.13. Graph

### 7.14.3. Complete graph

For this graph, a root node is created, and used to hang a number of nodes from. Then, two nodes are selected, hanging from the center, with the requirement that the id of the first is less than the id of the next. This is to prevent double relationships and self relationships. Using said match, relationships between all these nodes are created. Lastly, the center node and all relationships connected to it are removed.

Query.

    CREATE center
    foreach( x in range(1,6) :

    CREATE leaf={count : x}, center-[:X]->leaf
    )
    ==== center ====
    MATCH leaf1<--center-->leaf2
    WHERE id(leaf1)<id(leaf2)
    CREATE leaf1-[:X]->leaf2
    ==== center ====
    MATCH center-[r]->()
    DELETE center,r;

Nothing is returned by this query.

Result

Nodes created: 7
Relationships created: 21
Properties set: 6
Nodes deleted: 1
Relationships deleted: 6
0 ms
`(empty result)`

Figure 7.14. Graph

### 7.14.4. 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

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 ms
`8`

Figure 7.15. Graph

Copyright © 2013 Neo Technology

Prev | Up | Next
| Home |