Limitations

• Google Sheets has quota, latency, and API rate limits.
• Sheet updates are asynchronous; the application should read its local state.
• SQLite is local to the service and is not a distributed coordination layer.
• Schema changes, manual edits, and conflicting updates still need an operational policy from the application.

What Hikoutei is not

• Not a general-purpose database replacement.
• Not a Prisma/JPA clone.
• Not a general-purpose Google Sheets API wrapper — use @googleapis/sheets or google-spreadsheet for raw spreadsheet access.
• Not a transaction-safe database on top of Sheets. The SQLite commit is the application success boundary; remote delivery is at-least-once and asynchronous, and compare-and-set evidence is not a true distributed transaction.
• Not a full ORM: the EntityManager is an ORM-style facade over scalar entities. Entity definitions are scalar-only (string / number / boolean / date); v1 permits uniqueness only on the primary/business key.
• Not a relational engine: relations, joins, populate(), migrations, cascades, bulk/ORM query builders, and raw SQL are unsupported in this milestone. Sheets is never a live query database.