图数据库查询语言

本文介绍图数据库支持的gremlin和Cypher查询语言。

初始化数据#

可使用gremlin api执行

gremlin api#

POST http://localhost:8080/gremlin

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{"gremlin":"这里是语句",
 "bindings": {},
"language": "gremlin-groovy",
"aliases": {
		"graph": "graphname", 
		"g": "__g_graphname"
	}
}

schema#

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schema = hugegraph.schema()

schema.propertyKey("name").asText().ifNotExist().create()
schema.propertyKey("age").asInt().ifNotExist().create()
schema.propertyKey("time").asInt().ifNotExist().create()
schema.propertyKey("reason").asText().ifNotExist().create()
schema.propertyKey("type").asText().ifNotExist().create()

schema.vertexLabel("character").properties("name", "age", "type").primaryKeys("name").nullableKeys("age").ifNotExist().create()
schema.vertexLabel("location").properties("name").primaryKeys("name").ifNotExist().create()

schema.edgeLabel("father").link("character", "character").ifNotExist().create()
schema.edgeLabel("mother").link("character", "character").ifNotExist().create()
schema.edgeLabel("battled").link("character", "character").properties("time").ifNotExist().create()
schema.edgeLabel("lives").link("character", "location").properties("reason").nullableKeys("reason").ifNotExist().create()
schema.edgeLabel("pet").link("character", "character").ifNotExist().create()
schema.edgeLabel("brother").link("character", "character").ifNotExist().create()

插入数据#

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// add vertices
Vertex saturn = graph.addVertex(T.label, "character", "name", "saturn", "age", 10000, "type", "titan")
Vertex sky = graph.addVertex(T.label, "location", "name", "sky")
Vertex sea = graph.addVertex(T.label, "location", "name", "sea")
Vertex jupiter = graph.addVertex(T.label, "character", "name", "jupiter", "age", 5000, "type", "god")
Vertex neptune = graph.addVertex(T.label, "character", "name", "neptune", "age", 4500, "type", "god")
Vertex hercules = graph.addVertex(T.label, "character", "name", "hercules", "age", 30, "type", "demigod")
Vertex alcmene = graph.addVertex(T.label, "character", "name", "alcmene", "age", 45, "type", "human")
Vertex pluto = graph.addVertex(T.label, "character", "name", "pluto", "age", 4000, "type", "god")
Vertex nemean = graph.addVertex(T.label, "character", "name", "nemean", "type", "monster")
Vertex hydra = graph.addVertex(T.label, "character", "name", "hydra", "type", "monster")
Vertex cerberus = graph.addVertex(T.label, "character", "name", "cerberus", "type", "monster")
Vertex tartarus = graph.addVertex(T.label, "location", "name", "tartarus")

// add edges
jupiter.addEdge("father", saturn)
jupiter.addEdge("lives", sky, "reason", "loves fresh breezes")
jupiter.addEdge("brother", neptune)
jupiter.addEdge("brother", pluto)
neptune.addEdge("lives", sea, "reason", "loves waves")
neptune.addEdge("brother", jupiter)
neptune.addEdge("brother", pluto)
hercules.addEdge("father", jupiter)
hercules.addEdge("mother", alcmene)
hercules.addEdge("battled", nemean, "time", 1)
hercules.addEdge("battled", hydra, "time", 2)
hercules.addEdge("battled", cerberus, "time", 12)
pluto.addEdge("brother", jupiter)
pluto.addEdge("brother", neptune)
pluto.addEdge("lives", tartarus, "reason", "no fear of death")
pluto.addEdge("pet", cerberus)
cerberus.addEdge("lives", tartarus)

创建索引#

创建索引，使用REST API：

POST http://localhost:8080/graphs/hugegraph/schema/indexlabels

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{
	"name": "characterAge",
	"base_type": "VERTEX_LABEL",
	"base_value": "character",
	"index_type": "RANGE",
	"fields": [
		"age"
	]
}

查询#

API 说明#

支持gremlin、sparql和Cypher api，推荐gremlin和Cypher

cypher api#

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http://127.0.0.1:8080/graphs/hugegraph/cypher?cypher=

eg:

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curl http://127.0.0.1:8080/graphs/hugegraph/cypher?cypher=MATCH%20(n:character)-[:lives]-%3E(location)-[:lives]-(cohabitants)%20where%20n.name=%27pluto%27%20return%20cohabitants.name

gremlin api#

POST http://localhost:8080/gremlin

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{"gremlin":"这里是语句",
 "bindings": {},
"language": "gremlin-groovy",
"aliases": {
		"graph": "graphname", 
		"g": "__g_graphname"
	}
}

sparql api#

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GET http://127.0.0.1:8080/graphs/hugegraph/sparql?sparql=SELECT%20*%20WHERE%20{%20}

1. 查询hercules的祖父

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g.V().hasLabel('character').has('name','hercules').out('father').out('father')

也可以通过repeat方式：

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g.V().hasLabel('character').has('name','hercules').repeat(__.out('father')).times(2)

cypher

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MATCH (n:character)-[:father]->()-[:father]->(grandfather) where n.name='hercules' return grandfather

2. Find the name of hercules's father

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g.V().hasLabel('character').has('name','hercules').out('father').value('name')

cypher

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MATCH (n:character)-[:father]->(father) where n.name='hercules' return father.name

3. Find the characters with age > 100

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g.V().hasLabel('character').has('age',gt(100))

cypher

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MATCH (n:character) where n.age > 10 return n

4. Find who are pluto's cohabitants

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g.V().hasLabel('character').has('name','pluto').out('lives').in('lives').values('name')

cypher

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MATCH (n:character)-[:lives]->(location)-[:lives]-(cohabitants) where n.name='pluto' return cohabitants.name

5. Find pluto can't be his own cohabitant

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pluto = g.V().hasLabel('character').has('name', 'pluto')
g.V(pluto).out('lives').in('lives').where(is(neq(pluto)).values('name')

// use 'as'
g.V().hasLabel('character').has('name', 'pluto').as('x').out('lives').in('lives').where(neq('x')).values('name')

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cypher> MATCH (src:character{name:"pluto"})-[:lives]->()<-[:lives]-(dst:character) RETURN dst.name

6. Pluto's Brothers

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pluto = g.V().hasLabel('character').has('name', 'pluto').next()
// where do pluto's brothers live?
g.V(pluto).out('brother').out('lives').values('name')

// which brother lives in which place?
g.V(pluto).out('brother').as('god').out('lives').as('place').select('god','place')

// what is the name of the brother and the name of the place?
g.V(pluto).out('brother').as('god').out('lives').as('place').select('god','place').by('name')

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MATCH (src:Character{name:"pluto"})-[:brother]->(bro:Character)-[:lives]->(dst)
RETURN bro.name, dst.name

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作者：Jadepeng
出处：jqpeng的技术记事本--http://www.cnblogs.com/xiaoqi
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