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
{"gremlin":"这里是语句",
"bindings": {},
"language": "gremlin-groovy",
"aliases": {
"graph": "graphname",
"g": "__g_graphname"
}
}
schema
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
// 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
{
"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
http://127.0.0.1:8080/graphs/hugegraph/cypher?cypher=
eg:
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
{"gremlin":"这里是语句",
"bindings": {},
"language": "gremlin-groovy",
"aliases": {
"graph": "graphname",
"g": "__g_graphname"
}
}
sparql api
GET http://127.0.0.1:8080/graphs/hugegraph/sparql?sparql=SELECT%20*%20WHERE%20{%20}
1. 查询hercules的祖父
g.V().hasLabel('character').has('name','hercules').out('father').out('father')
也可以通过repeat方式：
g.V().hasLabel('character').has('name','hercules').repeat(__.out('father')).times(2)
cypher
MATCH (n:character)-[:father]->()-[:father]->(grandfather) where n.name='hercules' return grandfather
2. Find the name of hercules's father
g.V().hasLabel('character').has('name','hercules').out('father').value('name')
cypher
MATCH (n:character)-[:father]->(father) where n.name='hercules' return father.name
3. Find the characters with age > 100
g.V().hasLabel('character').has('age',gt(100))
cypher
MATCH (n:character) where n.age > 10 return n
4. Find who are pluto's cohabitants
g.V().hasLabel('character').has('name','pluto').out('lives').in('lives').values('name')
cypher
MATCH (n:character)-[:lives]->(location)-[:lives]-(cohabitants) where n.name='pluto' return cohabitants.name
5. Find pluto can't be his own cohabitant
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')
cypher> MATCH (src:character{name:"pluto"})-[:lives]->()<-[:lives]-(dst:character) RETURN dst.name
6. Pluto's Brothers
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')
MATCH (src:Character{name:"pluto"})-[:brother]->(bro:Character)-[:lives]->(dst)
RETURN bro.name, dst.name
作者：Jadepeng
出处：jqpeng的技术记事本--http://www.cnblogs.com/xiaoqi
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