Question

我正在使用OrientDB 2.0。查询很简单，但我似乎无法弄明白。我有两个课程：User和UserGroup。为简化起见，User只有username和password属性，而UserGroup只有一个id属性。关系很简单：

User --- user_group --> UserGroup

其中user_group是连接User和UserGroup顶点的边缘类。

我想要做的是让用户拥有某个用户名和密码UserGroup.id等于 group1

到目前为止我所拥有的是：

select expand(in('user_group')[username='foo' and password='bar']) 
from UserGroup
where id = 'group1'

但这对我不起作用。我做错了什么？

Answer 1

create class User extends V
create property User.username string
create property User.password string

create class UserGroup extends V
create property UserGroup.id string

create class user_group extends E


create vertex User set username = 'foo', password = 'bar'
create vertex UserGroup set id = 'group1'

create edge user_group from (select from User where username = 'foo') to (select from UserGroup where id = 'group1')


select expand(in('user_group')[username='foo'][password='bar']) 
from UserGroup
where id = 'group1'

Answer 2

我想，经过几次尝试，我找到了答案：

select from 
   (select expand(in('user_group'))
    from UserGroup
    where id = 'group1')
where username='foo' and password='bar'

如果有人能提出更优雅的解决方案，那也很不错

Answer 3

select 
from (
     select expand(in('user_group')) 
     from UserGroup 
     where id = 'group1'
) 
where username='foo' and password='bar'

如何查询具有某些属性的邻居顶点？

3 个答案: