char
Use PostgreSQL char(n) for fixed-length strings, understand padding behavior, and choose it intentionally.
varchar and text
Choose between PostgreSQL varchar(n) and text, enforce length safely, and handle case-insensitive text with citext.
ENUM types
Use PostgreSQL enum types to restrict values, understand ordering/alterations, and choose enums vs lookup tables.
bytea and uuid
Store binary data with PostgreSQL bytea and use uuid for globally unique identifiers with safe generation options.