在OrientDB 3.0.x(x>5)中,是否可能有一条边,其一端也是边?这似乎是可能的,但文件中没有解释:
--Define vertex A,B,C
create class testVertexA extends V;
create class testVertexB extends V;
create class testVertexC extends V;
--Define EdgeA that connects 2 vertexes -A and B
create class testEdgeA extends E;
create property testEdgeA.in link testVertexA;
create property testEdgeA.out link testVertexB;
--Define EdgeB that connects EdgeA and vertex C - is this possible?
create class testEdgeB extends E;
create property testEdgeB.in link testVertexC;
create property testEdgeB.out link testEdgeA;
接下来,我们输入一些数据,看看这是否有效:
orientdb>插入testVertexA;
Inserted record '[testVertexA#225:0 v1]' in 0.000000 sec(s).
orientdb > insert into testVertexB;
Inserted record '[testVertexB#233:0 v1]' in 0.016000 sec(s).
orientdb > insert into testVertexC;
Inserted record '[testVertexC#241:0 v1]' in 0.000000 sec(s).
orientdb > insert into testEdgeA set in=#225:0, out=#233:0;
Inserted record '[testEdgeA#249:0{in:#225:0,out:#233:0} v1]' in 0.000000 sec(s).
orientdb > insert into testEdgeB set in=#241:0, out=#249:0;
Inserted record '[testEdgeB#257:0{in:#241:0,out:#249:0} v1]' in 0.000000 sec(s).
orientdb > select from testEdgeB;
+----+------+---------+------+------+
|# |@RID |@CLASS |in |out |
+----+------+---------+------+------+
|0 |#257:0|testEdgeB|#241:0|#249:0|
+----+------+---------+------+------+
1 item(s) found. Query executed in 0.0 sec(s).
orientdb > select from #241:0
+----+------+-----------+
|# |@RID |@CLASS |
+----+------+-----------+
|0 |#241:0|testVertexC|
+----+------+-----------+
1 item(s) found. Query executed in 0.0 sec(s).
orientdb > select from #249:0
+----+------+---------+------+------+
|# |@RID |@CLASS |in |out |
+----+------+---------+------+------+
|0 |#249:0|testEdgeA|#225:0|#233:0|
+----+------+---------+------+------+
1 item(s) found. Query executed in 0.0 sec(s).
有人能肯定这一点吗。谢谢
