It is very simple SQL, as mentioned before.
Actually there are two ways how to do that.
One is via
t_object.ParentID and the other one is via x,y coordinates on
t_diagramobjects. The second way reflects "Diagram reality", the first one "Browser reality".
"Diagram reality" approach solves several potential problems:
1. if some elements have been removed from diagram but not deleted from model
2. if you ever need activities to be stored somewhere else than under swimlanes
3. if you ever interested in ordered list of activities as they appear on diagram (left->right, top->down)
This is good case for learning SQL:
- "Browser reality" approach needs
t_object table only
- "Diagram reality" approach needs
t_object and
t_diagramobjectsI definitelly recommend learning so called "
macros" from this source (most important one is
#Branch# macro, which will solve the poblem of pointing your SQL to particular model branch):
https://sparxsystems.com/enterprise_architect_user_guide/15.2/navigation/creating_filters.html