In Relation Based Edge, how to get Source Node

[pelva]

Hi,
My understanding: self is the target semantic element.
As shown in the figure below, there are several available variables, and they all seem to point to a DDiagram.
I want to know what the "diagram" variable below represents.
Is it the current Relation Based Edge?
If I want to get the Source Node, what should I do?
I tried using diagram.sourceNode, but I compared self with diagram.sourceNode.target and found that they are not consistent.
please help me,thank you

[lredor]

You're right, all the variables, diagram, viewpoint and viewPoint, point to the DDiagram that you are currently work on. It is not necessarily necessary here.

In the target finder expression, you must start from aql:self that is the semantic element of the source of this edge. In other words, you must define the expression which allows, from a source semantic element, to find the semantic elements which will be the targets of this relationship.

If you want, you have an example in Flow Designer:

[pelva]

Flow Designer is a great example and I learned a lot from it.
The Edge I implemented is slightly more complicated, it and the connected endpoint are both calculated, so I want to get the Source Node in order to determine the parent container object. In short, thank you for your reply.

[pelva]

I think I know how to implement it. Edge has not been created in General->Target Finder Expression, so I can get the SourceView in Advanced->Precondition Expression for further processing.