Query and analyze a graph

Prerequisites

You have logged on to the database as described in the Quick Start. For more information, see Log on to a database.

Gremlin

The following example statements are for GDB instances that use the Gremlin engine.

Vertex queries

• Count the number of vertices.

  g.V().count()

• Count the number of vertices of each type.

  g.V().group().by(label).by(count())
  g.V().groupCount().by(label)

• Query all vertices.

  g.V().limit(100)

• Query vertices with a specific label.

  g.V().hasLabel('person')

• Query a vertex by its ID.

  g.V('123')

• Filter vertices by property.

  g.V().has('name','Zhang San')

Edge queries

• Count the number of edges.

  g.E().count()

• Count the number of edges of each type.

  g.E().group().by(label).by(count())

• Query all edges.

  g.E()

• Query edges with a specific label.

  g.E().hasLabel('connect')

• Query an edge by its ID.

  g.E('12')

• Query the edges associated with a vertex.

  g.V('123').outE('connect')

• Query a path.

  g.V('123').outE('connect').path()

Property queries

• Query the properties of a vertex.

  g.V('123').valueMap(true)

Sort queries

• Sort by a property field.

  g.V().has('name','Zhang San').outE('connect').order().by('weight', decr).valueMap(true)

Add a vertex

• Add a vertex.

  g.addV('person').property(id,'23').property('name','Li Si')

Delete vertices

• Delete a specific vertex.

  g.V('123').drop()

• Delete vertices by property.

  g.V().has('person').property('age', values('18')).drop()

• Delete all vertices in batches.

  g.V().drop().limit(1024)

Add an edge

• Add an edge.

  g.addE('connect').property('weight', '4').from(g.V('12')).to(g.V('16'))

Delete an edge

• Delete an edge.

  g.E('23').drop()

OpenCypher

The following example statements are for GDB instances that use the OpenCypher engine.

Vertex queries

• Count the number of vertices.

  MATCH (n) return count(n)

• Count the number of vertices of each type.

  MATCH (n) return labels(n), count(*)

• Query all vertices (not recommended).

  MATCH (n) return n limit 10

• Query vertices with a specific label.

  MATCH (n:person) return n

• Filter vertices by property.

  MATCH (n:person {firstName: "Carlos"}) return n;

Edge queries

• Count the number of edges.

  MATCH (n)-[r]->(m) return count(r)

• Count the number of edges of each type.

  MATCH (n)-[r]->(m) return type(r), count(*)

• Query all edges.

  MATCH (n)-[r]->(m) return r

• Query edges with a specific label.

  MATCH (n)-[r:knows]->(m) return r

• Query edges by edge property.

  MATCH (n)-[r:knows {creationDate:1274809046847}]->(m) return r

• Query the edges associated with a vertex.

  MATCH (n:person {firstName: "Carlos"})-[r]->(m) return r

• Query a path.

  MATCH p=(n:person {firstName: "Carlos"})-[r]->(m) return p

Property queries

• Query the properties of a vertex.

  MATCH (n:person {firstName: "Carlos"}) return properties(n) limit 2;

Sort queries

• Sort by a property field.

  MATCH (n:person {firstName: "Mahinda"})-[r]-(m) return m order by m.locationIP

Add a vertex

• Add a vertex.

  CREATE (n:Person {name: 'Andy', title: 'Developer'})

Delete vertices

• Delete a specific vertex.

  MATCH (n:Person {name: 'tom'})
  DELETE n

• Remove a property from a vertex.

  MATCH (a {name: 'Andy'})
  REMOVE a.age
  RETURN a

• Delete vertices in batches.

  MATCH (n:Person )
  DELETE n
  LIMIT 10

Add an edge

• Add an edge.

  MATCH
    (a:Person),
    (b:Person)
  WHERE a.name = 'A' AND b.name = 'B'
  CREATE (a)-[r:RELTYPE]->(b)
  RETURN type(r)

Delete an edge

• Delete an edge.

  MATCH (n {name: 'Andy'})-[r:KNOWS]->()
  DELETE rg.E('23').drop()