Multi-value fields stored as arrays, not comma-delimited strings

Comma-delimited strings cannot be indexed for faceted search, cannot be filtered in SQL without LIKE '%value%' scans, and produce false matches (Parking matches No Parking). Consumer APIs that expect arrays get strings and either crash or display literal WiFi, Parking, Outdoor Seating as a single tag. Migrating later requires a string-split backfill that is brittle when values themselves contain commas, and every downstream integration that already parsed the string must be updated simultaneously.

Store multi-value fields as native arrays in Postgres (text[]) or a relational join table, never as delimited strings. Define them as array types in your Prisma schema at prisma/schema.prisma and update API serializers to emit JSON arrays. Migrate existing comma-delimited rows with a one-time SQL job that splits and trims, then drops the old column.

model Listing {
  id         String   @id @default(cuid())
  name       String
  categories String[]
  amenities  String[]
}