我一直在使用OrientDB sql查询来获取一个结果集,该结果集不仅包含顶点,还包含它们之间存在的内部边.
查询可以表示为:
我想要所有与之相关的顶点project
(没有项目本身)以及结果中包含的顶点之间的所有边
这是我如何实现它,但我认为这不是正确的方法.
select expand($union) let $vertices = ( select from ( traverse both() from (select from V where label = 'project') ) skip 1 ), $edges = ( select from ( select from E where @rid in ( select bothE() from ( select from ( traverse both() from (select from V where label = 'project') ) skip 1 ) ) ) where out in ( select from ( traverse both() from (select from V where label = 'project') ) skip 1 ) and in in ( select from ( traverse both() from (select from V where label = 'project') ) skip 1 ) ), $union = unionall($vertices, $edges)
并且预期的结果是:
此解决方案的问题:
我必须多次遍历图形(首先获取顶点,然后获取边缘以最终合并结果)
基本查询select from V where label = 'project'
也会执行多次.
有没有更好的方法来解决这个用例?
谢谢.
试试这个查询:
select expand($c) let $a=(traverse both(),bothE() from (select from V where label="project")), $b=(traverse bothE() from (select from V where label="project")), $c=difference($a,$b)