A table design is a statement about identity and access. Name what one row represents before choosing its columns. A reservation row might represent one buyer's hold on one seat; its primary key identifies the hold, while a separate constraint protects the seat invariant. For a mapping service, a short code identifies one destination and needs a uniqueness rule even if random collisions are rare.
Model the fields needed to answer the stated query. An event table often needs both an event ID for deduplication and a timestamp for ordering or retention. These fields solve different problems. A timestamp isn't always unique, and a generated ID doesn't by itself establish event time. The structured worksheet accepts columns and key fields in any order. Add extra useful fields if needed, but keep the required identity and access path explicit.