sql - 东方数据库 SQL : How to find vertices and create edges between them?

Question

在我的数据库上运行以下查询:

SELECT @rid AS module_rid, out('USES').out('BELONGS_TO').@rid AS project_rid FROM MODULES LIMIT 10

我收到了以下回复:

module_rid | project_rid
-----------|----------------
#12:0      | []
#12:1      | []
#12:2      | []
#12:3      |        
#11:48677  | #11:48677 #11:48677 #11:48677 #11:48677 #11:48677 ..More(49)
#12:4      |        
#11:48677  | #11:48677 #11:48677 #11:48677 #11:48677 #11:48677 ..More(49)
#12:5      |        
#11:2526   | #11:2526 #11:2526 #11:47148 #11:47148 #11:25338 ..More(30)
#12:6      | []

如何在模块和它们所依赖的项目(它们至少使用项目的一个模块)之间创建边(例如 RELIES_ON)？

Answer 1

create class Module extends V
create class Project extends V

create class Uses extends E
create class ReliesOn extends E


create vertex Module set name = 'm1'
create vertex Module set name = 'm2'
create vertex Module set name = 'm3'

create vertex Project set name = 'p1'
create vertex Project set name = 'p2'
create vertex Project set name = 'p3'


create edge Uses from (select from Module where name = 'm2') to (select from Project where name = 'p1')
create edge Uses from (select from Module where name = 'm3') to (select from Project where name = 'p2')
create edge Uses from (select from Module where name = 'm3') to (select from Project where name = 'p3')

我知道上述情况与您的情况略有不同，但我相信这足以了解您问题的可能解决方案。

您可以定义一个函数createEdges，例如:

var gdb = orient.getGraph();

if(to.size() != 0){
    var command = "create edge ReliesOn from " + from + " to " + to;
    gdb.command("sql", command);
}
return;

现在以下查询将在创建边时查找顶点:

select from (
    select @rid as module_rid, out('Uses').@rid as project_rid from Module
)
let $ce = createEdges(module_rid, project_rid)

---

更新:

如果您想确保“to”不包含重复项，您可以:

select from (
    select @rid as module_rid, $aux[0].set.@rid as project_rid from Module
    let $aux = ( select set(out('Uses')) from $current )
) 
let $ce = createEdges(module_rid, project_rid)