java - Gremlinepipeline 两个顶点之间的边

Question

在java代码中使用Gremline管道检查顶点之间的边？我能够创建边缘，但如果我们再次给出相同的顶点，则会创建新的边缘。我想在两个顶点之间创建一条独特的边。有什么帮助吗？我正在使用orientDB

Answer 1

您可以在 Edge 类上创建一个唯一索引来提供该约束

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')