I use JSONB columns for similar use-cases, but to play devil's advocate, you can accomplish that a fourth way, which is almost certainly better than 1 or 2. A table for fields, one row per field. A table for forms, which has a many-to-many relation to fields. Entries in a link table compose a form of arbitrary fields. Answers can be stored in a separate responses table, indexed by form_id and column_id. I don't know enough about database implementation to speculate on how that would perform at scale, but conceptually that's how I think of the problem.