ER (min,max) Practice

The (min,max) notation (Kemper, Funktionalitäten (7))

For a relationship R ⊆ E₁ × … × E_n, the pair (min_i, max_i) on the edge next to entity E_i states that every e_i ∈ E_i must appear in at least min_i and at most max_i tuples of R. "*" denotes "no upper bound".

Functionalities

partial functions R: E₁ × … × E_k-1 × E_k+1 × … × E_n &to; E_k expresses that for any fixed combination of the other entities, e_k is unique — i.e., no two tuples agree on every position except k. Functionalities are independent of (min,max); they are a separate constraint that the instance must respect.

Mode A — Infer (min,max) from an instance

The diagram shows the functionality letters (1 / N / M / …) on every edge. Given the instance, enter the tightest (min, max) pair for every edge in the diagram inputs. Correctly entered pairs turn green on Check, wrong ones red.

Mode B — Build an instance and pick the valid partial functions

The diagram shows (min,max) labels and the functionality letters. Two tasks: (1) type tuples into the text area that respect every (min,max) bound and every "1"; (2) from the listed possible partial function (n−1) &to; 1, tick exactly those whose target carries "1" in the diagram. The checker verifies both. Tuples must be distinct.