resource
- 入门
- 详细（或速查，目录是按字母序的所有steps）TinkerPop Documentation (apache.org) graph-traversal-steps
Germlin core steps
来自TinkerPop Documentation (apache.org) graph-traversal-steps
As Step
provide a label to the step that can later be accessed by steps and data structures
AddEdge Step
https://tinkerpop.apache.org/docs/3.5.3/reference/#addedge-step
add edge
eg: Add co-developer edge with a year-property between marko and his collaborators.
gremlin>
g.V(1).as('a').out('created').in('created').where(neq('a')).addE('co-developer').from('a').property('year',2009)
==>e[13][1-co-developer->4]
==>e[14][1-co-developer->6]
Graph Step (V E)
read vertices, V(), or edges, E(), from the graph
Has Step
https://tinkerpop.apache.org/docs/3.5.3/reference/#has-step
filter vertices, edges, and vertex properties based on their properties
Select Step
https://tinkerpop.apache.org/docs/3.5.3/reference/#select-step
select() select an element based on
- a/many static key
- a traversal that emits a key
eg: a static key
gremlin> g.V().out().out()
==>v[5]
==>v[3]
gremlin> g.V().out().out().path()
==>[v[1],v[4],v[5]]
==>[v[1],v[4],v[3]]
gremlin> g.V().as('x').out().out().select('x')
==>v[1]
==>v[1]
gremlin> g.V().out().as('x').out().select('x')
==>v[4]
==>v[4]
gremlin> g.V().out().out().as('x').select('x') // pointless
==>v[5]
==>v[3]
eg: many static keys
gremlin> g.V().as('a').out().as('b').out().as('c').select('a','b','c')
==>[a:v[1],b:v[4],c:v[5]]
==>[a:v[1],b:v[4],c:v[3]]
