PostgreSQL column type definitions with integer (integer, smallint, bigint, serial, smallserial, bigserial), text (text, varchar, char), numeric (numeric, real, doublePrecision), JSON (json, jsonb), date/time (time, timestamp, date, interval), geometric (point, line), enum types; identity columns with GENERATED ALWAYS/BY DEFAULT; default values via .default(), .$defaultFn(), .$onUpdateFn(); constraints (.notNull(), .primaryKey()); type customization via .$type<T>()