Cypher 和 nGQLGraph

基本概念对比Graph

概念名称	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

图基本操作Graph

操作	Cypher	nGQL
列出所有 labels/tags	MATCH (n) RETURN distinct labels(n); call db.labels();	SHOW TAGS
插入指定类型的点	CREATE (:Person {age: 16})	INSERT VERTEX `<tag_name>` (prop_name_list) VALUES `<vid>`:(prop_value_list)
插入指定类型的边	CREATE (src)-[:LIKES]->(dst) SET rel.prop = V	INSERT EDGE `<edge_type>` ( prop_name_list ) VALUES `<src_vid>` -> `<dst_vid>`[`@<rank>`]: ( prop_value_list )
删除点	MATCH (n) WHERE ID(n) = vid DETACH DELETE n	DELETE VERTEX `<vid>`
删除边	MATCH ()-[r]->() WHERE ID(r)=edgeID DELETE r	DELETE EDGE `<edge_type>` `<src_vid>` -> `<dst_vid>`[`@<rank>`]
更新点属性	SET n.name = V	UPDATE VERTEX `<vid>` SET `<update_columns>`
查询指定点的属性	MATCH (n) WHERE ID(n) = vid RETURN properties(n)	FETCH PROP ON `<tag_name>` `<vid>`
查询指定边的属性	MATCH (n)-[r]->() WHERE ID(r)=edgeID return properties(r)	FETCH PROP ON `<edge_type>` `<src_vid>` -> `<dst_vid>`[`@<rank>`]
查询指定点的某一类关系	MATCH (n)-[r:edge_type]->() WHERE ID(n) = vid	GO FROM `<vid>` OVER `<edge_type>`
指定点的某一类反向关系	MATCH (n)<-[r:edge_type]-() WHERE ID(n) = vid	GO FROM `<vid>` OVER `<edge_type>` REVERSELY
指定点某一类关系第 N-Hop 查询	MATCH (n)-[r:edge_type*N]->() WHERE ID(n) = vid return r	GO N STEPS FROM `<vid>` OVER `<edge_type>`
两点路径	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 *

示例查询Graph

示例使用以下数据:

插入数据

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

# 插入边
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)
 ```

- 删除点

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

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

更新点的属性

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

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

查看点的属性

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}│
  └────────────────────────────────────────────┘

查询 hercules 祖父的姓名

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"   │
      └──────────┘

查询 hercules 父亲的姓名

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" │
      └──────────┘

查询百岁老人的姓名

nebula> # coming soon

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

找出 pluto 和谁住

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"│
      └──────────┘

查询 Pluto 的兄弟们以及他们的居住地

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"    │
      └─────────────────────────┘

最后更新: 2020年6月23日