Comparison Between Cypher and nGQL

Conceptual Comparisons

Name	Cypher	nGQL
vertex, node	node	vertex
edge, relationship	relationship	edge
vertex type	label	tag
edge type	relationship type	edge type
vertex identifier	node id generated by default	vid
edge identifier	edge id generated by default	src, dst, rank

Basic Graph Operations

Operations	Cypher	nGQL
List all labels/tags	MATCH (n) RETURN distinct labels(n); call db.labels();	SHOW TAGS
Insert a vertex with a specified type	CREATE (:Person {age: 16})	INSERT VERTEX <tag_name> (prop_name_list) VALUES <vid>:(prop_value_list)
Insert an edge with specified edge type	CREATE (src)-[rel:LIKES]->(dst) SET rel.prop = V	INSERT EDGE <edge_type> ( prop_name_list ) VALUES <src_vid> -> <dst_vid>[@<rank>]: ( prop_value_list )
Delete a vertex	MATCH (n) WHERE ID(n) = vid DETACH DELETE n	DELETE VERTEX <vid>
Delete an edge	MATCH ()-[r]->() WHERE ID(r)=edgeID DELETE r	DELETE EDGE <edge_type> <src_vid> -> <dst_vid>[@<rank>]
Update a vertex property	SET n.name = V	UPDATE VERTEX <vid> SET <update_columns>
Fetch vertex prop	MATCH (n) WHERE ID(n) = vid RETURN properties(n)	FETCH PROP ON <tag_name> <vid>
Fetch edge prop	MATCH (n)-[r]->() WHERE ID(r)=edgeID return properties(r)	FETCH PROP ON <edge_type> <src_vid> -> <dst_vid>[@<rank>]
Query a vertex along specified edge type	MATCH (n)-[r:edge_type]->() WHERE ID(n) = vid	GO FROM <vid> OVER <edge_type>
Query a vertex along specified edge type reversely	MATCH (n)<-[r:edge_type]-() WHERE ID(n) = vid	GO FROM <vid> OVER <edge_type> REVERSELY
Get the N-Hop along a specified edge type	MATCH (n)-[r:edge_type*N]->() WHERE ID(n) = vid return r	GO N STEPS FROM <vid> OVER <edge_type>
Find path between two vertices	MATCH p =(a)-[]->(b) WHERE ID(a) = a_vid AND ID(b) = b_vid RETURN p	FIND ALL PATH FROM <a_vid> TO <b_vid> OVER *

Example Queries

The example queries are based on the graph below:

• Insert data

# insert vertex
nebula> INSERT VERTEX character(name, age, type) VALUES hash("saturn"):("saturn", 10000, "titan"), hash("jupiter"):("jupiter", 5000, "god");

# insert edge
nebula> INSERT EDGE father() VALUES hash("jupiter")->hash("saturn"):();

// cypher
cypher> CREATE (src:character {name:"saturn", age: 10000, type:"titan"})
      > CREATE (dst:character {name:"jupiter", age: 5000, type:"god"})
      > CREATE (src)-[rel:father]->(dst)
 ```

- Delete vertex

```ngql
nebula> DELETE VERTEX hash("prometheus");

cypher> MATCH (n:character {name:"prometheus"})
        > DETACH DELETE n

• Update vertex

nebula> UPDATE VERTEX hash("jesus") SET character.type = 'titan';

cypher> MATCH (n:character {name:"jesus"})
      > SET n.type = 'titan'

• Fetch vertices properties

nebula> FETCH PROP ON character hash("saturn");
  ===================================================
  | character.name | character.age | character.type |
  ===================================================
  | saturn         | 10000         | titan          |
  ---------------------------------------------------

cypher> MATCH (n:character {name:"saturn"})
      > RETURN properties(n)
  ╒════════════════════════════════════════════╕
  │"properties(n)"                             │
  ╞════════════════════════════════════════════╡
  │{"name":"saturn","type":"titan","age":10000}│
  └────────────────────────────────────────────┘

• Find the name of hercules's grandfather

nebula> GO 2 STEPS FROM hash("hercules") OVER father YIELD  $$.character.name;
    =====================
    | $$.character.name |
    =====================
    | saturn            |
    ---------------------

cypher> MATCH (src:character{name:"hercules"})-[r:father*2]->(dst:character)
      > RETURN dst.name
      ╒══════════╕
      │"dst.name"│
      ╞══════════╡
      │"satun"   │
      └──────────┘

• Find the name of hercules's father

nebula> GO FROM hash("hercules") OVER father YIELD $$.character.name;
    =====================
    | $$.character.name |
    =====================
    | jupiter           |
    ---------------------

cypher> MATCH (src:character{name:"hercules"})-[r:father]->(dst:character)
      > RETURN dst.name
      ╒══════════╕
      │"dst.name"│
      ╞══════════╡
      │"jupiter" │
      └──────────┘

• Find the the centenarians' name.

nebula> # coming soon

cypher> MATCH (src:character)
      > WHERE src.age > 100
      > RETURN src.name
      ╒═══════════╕
      │"src.name" │
      ╞═══════════╡
      │  "saturn" │
      ├───────────┤
      │ "jupiter" │
      ├───────────┤
      │ "neptune" │
      │───────────│
      │  "pluto"  │
      └───────────┘

• Find who live with pluto

nebula> GO FROM hash("pluto") OVER lives YIELD lives._dst AS place | GO FROM $-.place OVER lives REVERSELY WHERE \
      > $$.character.name != "pluto" YIELD $$.character.name AS cohabitants;
    ===============
    | cohabitants |
    ===============
    | cerberus    |
    ---------------

cypher> MATCH (src:character{name:"pluto"})-[r1:lives]->()<-[r2:lives]-(dst:character)
      > RETURN dst.name
      ╒══════════╕
      │"dst.name"│
      ╞══════════╡
      │"cerberus"│
      └──────────┘

• Find pluto's brother and their habitations?

nebula> GO FROM hash("pluto") OVER brother YIELD brother._dst AS god | \
      > GO FROM $-.god OVER lives YIELD $^.character.name AS Brother, $$.location.name AS Habitations;
    =========================
    | Brother | Habitations |
    =========================
    | jupiter | sky         |
    -------------------------
    | neptune | sea         |
    -------------------------

cypher> MATCH (src:Character{name:"pluto"})-[r1:brother]->(bro:Character)-[r2:lives]->(dst)
      > RETURN bro.name, dst.name
      ╒═════════════════════════╕
      │"bro.name"    │"dst.name"│
      ╞═════════════════════════╡
      │ "jupiter"    │  "sky"   │
      ├─────────────────────────┤
      │ "neptune"    │ "sea"    │
      └─────────────────────────┘