Databases

An Acore database contract declares the schema you want and its version. The Axiom CLI checks and builds it offline, applies it to a PostgreSQL or SQLite database as a versioned migration, and reports status and history. An Acore backend then reads and writes those tables through typed storage declarations instead of SQL strings.

The contract lifecycle

Diagram source

flowchart TD
  A[Schema and version in Acore] --> B[axiom database check and build]
  B --> C[axiom database migrate]
  C --> D[status and history]
  D --> E{Next change}
  E -->|Edit the schema| F[New version in source]
  F --> B
  E -->|Undo| G[rollback publishes a new version]
  G --> D
  D --> H[Backend storage declarations]
  H --> I[Typed application storage]

1. Declare the schema in an .acore file beside an AxiomDeps.toml with type = "database". project(id: ..., version: ...) names the contract and its version.
2. Check and build offline with axiom database check and axiom database build. Neither connects to a database.
3. Migrate with axiom database migrate (or axiom run). The change is validated on a disposable copy, then applied as one versioned migration.
4. Observe with status (applied and working versions, pending changes, drift) and history (migrations, compensating rollbacks, failed attempts).
5. Change or undo. Every schema change needs a new version. rollback publishes another new version; it never rewrites history or restores deleted values.
6. Use the tables from a backend through storage declarations. The CLI checks them against the compiled schema and migrates the linked database before the backend accepts requests.

Validation and review always come before a change reaches your database. Keep backups and test recovery for data you need to retain.

From a request to a table

Diagram source

flowchart LR
  A[GET /tasks endpoint] --> B[listTasks action]
  B --> C[Resources.tasks.list operation]
  C --> D[storage tasks: select list]
  D --> E[main.tasks table]

In the task app, the endpoint calls a managed action. The action awaits a resource operation, and the storage declaration implements that operation as a typed select on main.tasks. The runtime binds every input as a parameter and adds the authenticated tenant to the query. You never write SQL text for application queries.

Choose an engine

Both engines use the same commands, version rules and storage declarations. Windows, hosted-provider capabilities and nontransactional migration stages keep their own qualification gates. There is no MySQL or MariaDB adapter.

Where database work runs

A passing browser preview does not prove database persistence, and a local run does not qualify a production deployment.

Next steps

• Create your first database with SQLite.
• Read the database contract reference.
• Connect a backend in Migrations and persistence.
• Keep an existing schema with the existing database guide.