04 Try it yourself Interactive
Three students, two projects, and the same four attempted links every time: (S1,P1), (S1,P2), (S2,P1), (S3,P2). Pick a cardinality ratio from the tabs and step through them. Each attempt is either drawn or refused, and the narration names the label that decided it. The last two steps switch STUDENT’s participation from partial to total over whatever links survived. Watch attempt 3 in particular: it is legal under M:N and refused under 1:N, which is the constraint doing real work rather than decorating a picture. Nothing plays on its own. Next, Back and Reset, or the arrow keys.