两个顶点之间的Gremlinepipeline边缘

Question

To check the edge between the vertex using Gremline pipeline in java code? I am able to create the edges but if we give the same vertex again the new edge will be created. I want to create a unique edge between the 2 vertex. Any help? I am using orientDB

Answer 1

You can create a unique index on the Edge class that will give you that constraint

create class Foo extends V
create class FooEdge extends E
create property FooEdge.in LINK
create property FooEdge.out LINK

create index FooEdge_in_out on FooEdge (out,in) unique
insert into Foo set name = 'Foo1'
insert into Foo set name = 'Foo2'
create edge FooEdge from (select from Foo where name = 'Foo1') to (select from Foo where name = 'Foo2')
/* fail */
create edge FooEdge from (select from Foo where name = 'Foo1') to (select from Foo where name = 'Foo2')