1. Cypher Query Language
Chicago Graph Database Meet-Up
Max De Marzi

2. What is Cypher?
• Graph Query Language for Neo4j
• Aims to make querying simple

3. Design Decisions
Pattern matching
A
B C

4. Design Decisions
Pattern matching

5. Design Decisions
Pattern matching

6. Design Decisions
Pattern matching

7. Design Decisions
Pattern matching

8. Design Decisions
ASCII-art patterns
() --> ()

9. Design Decisions
Directed relationship
A B
(A) --> (B)

10. Design Decisions
Undirected relationship
A B
(A) -- (B)

11. Design Decisions
specific relationships
LOVES
A B
A -[:LOVES]-> B

12. Design Decisions
Joined paths
A B C
A --> B --> C

13. Design Decisions
multiple paths
A
B C
A --> B --> C, A --> C
A --> B --> C <-- A

14. Design Decisions
Variable length paths
A B
A B
A B
...
A -[*]-> B

15. Design Decisions
Optional relationships
A B
A -[?]-> B

16. Mutating Cypher
New in Neo4j 1.8

17. Create Nodes
CREATE turtle1 = {name : 'Donatello'},
turtle2 = {name : ‘Michelangelo'}, Cypher
turtle3 = {name : ‘Raphael'},
turtle4 = {name : ‘Leonardo'}
The Ninja Turtles

18. Create Relationships
START t1 = node(1), t2 = node(2),
t3 = node(3), t4 = node(4)
CREATE s = {name: ‘Splinter’ },
t1-[r:DISCIPLE]->s,
Cypher
t2-[r:DISCIPLE]->s,
t3-[r:DISCIPLE]->s,
t4-[r:DISCIPLE]->s
The Ninja Turtles
are disciples of
Splinter

19. Delete Nodes
START s = node:nodes(name = ‘Shredder’)
DELETE s Cypher
Shredder is defeated

20. Update Properties
START t1 = node(0), t2 = node(2)
SET t1.weapon = ‘Bo Staff’, t2.hungry = ‘Yes’ Cypher
Donatello uses the Bo Staff
Michelangelo is always hungry

21. Delete Properties
START t2 = node(2)
DELETE t2.hungry Cypher
Michelangelo nom nom nom

22. Using Relate
START turtles = node(1,2,3,4)
RELATE turtles-[r:LOVE]->pizza Cypher
The Ninja Turtles
love pizza
A pizza node and 4
relationships are
created

23. Using Relate again
START turtles = node(1,2,3,4)
RELATE turtles-[r:LOVE]-(pizza Cypher
{name:’Supreme’})
The Ninja Turtles
love pizza
A pizza node with
name “Supreme”
and 4 relationships
are created

24. Questions?
maxdemarzi.com