When there are two kind of relationship between two classes

[swithun-liu]

I want to describe the relationships like this

so I write

the new relationship --o will cover the former relationship <|-- , only the latter relationship will be displayed

[jgreywolf]

I believe that OP is referring to a setup like this:

classDiagram class A class B B <|-- A A --o B

Live Editor

With the caveat that the second relation is displayed like in the image