sqlite-utils/docs/migrations.rst

.. _migrations:

====================
 Database migrations
====================

``sqlite-utils`` includes a small migration system for applying repeatable changes to SQLite database files.

A migration is a Python function that receives a :class:`sqlite_utils.Database` instance. Migrations are grouped into named sets using the :class:`sqlite_utils.Migrations` class, and each applied migration is recorded in the ``_sqlite_migrations`` table in that database.

.. _migrations_python:

Applying migrations in Python
=============================

Create a :class:`sqlite_utils.Migrations` object, decorate migration functions with it and call ``.apply(db)`` against a :class:`sqlite_utils.Database` instance:

.. code-block:: python

    from sqlite_utils import Database, Migrations

    migrations = Migrations("creatures")

    @migrations()
    def create_table(db):
        db["creatures"].create(
            {"id": int, "name": str, "species": str},
            pk="id",
        )

    @migrations()
    def add_weight(db):
        db["creatures"].add_column("weight", float)

    db = Database("creatures.db")
    migrations.apply(db)

Running ``migrations.apply(db)`` repeatedly is safe. Migrations that already have a matching ``migration_set`` and ``name`` row in ``_sqlite_migrations`` will be skipped.

The name passed to ``Migrations("creatures")`` identifies that set of migrations. Use a name that is unique for your project, since multiple migration sets can be applied to the same database.

Migration functions are applied in the order their decorators run. The function name is used as the migration name unless you pass one explicitly:

.. code-block:: python

    @migrations(name="001_create_table")
    def create_table(db):
        db["creatures"].create({"id": int, "name": str}, pk="id")

You can also stop before a named migration:

.. code-block:: python

    migrations.apply(db, stop_before="add_weight")

Migration files
===============

The ``sqlite-utils migrate`` command looks for migration sets in Python files, usually named ``migrations.py``. A migration file should define one or more :class:`sqlite_utils.Migrations` objects:

.. code-block:: python

    from sqlite_utils import Migrations

    migrations = Migrations("creatures")

    @migrations()
    def create_table(db):
        db["creatures"].create(
            {"id": int, "name": str, "species": str},
            pk="id",
        )

    @migrations()
    def add_weight(db):
        db["creatures"].add_column("weight", float)

Applying migrations using the CLI
=================================

Run migrations using the ``sqlite-utils migrate`` command:

.. code-block:: bash

    sqlite-utils migrate creatures.db path/to/migrations.py

The first argument is the database file. The remaining arguments can be paths to migration files or directories containing migration files.

If you omit migration paths, ``sqlite-utils`` searches the current directory and subdirectories for files called ``migrations.py``:

.. code-block:: bash

    sqlite-utils migrate creatures.db

You can also pass a directory. Every ``migrations.py`` file in that directory tree will be considered:

.. code-block:: bash

    sqlite-utils migrate creatures.db path/to/project/

Running the command repeatedly is safe. Migrations that already have a matching ``migration_set`` and ``name`` row in ``_sqlite_migrations`` will be skipped.

Listing migrations
==================

Use ``--list`` to show applied and pending migrations without running them:

.. code-block:: bash

    sqlite-utils migrate creatures.db --list

Example output:

.. code-block:: output

    Migrations for: creatures

      Applied:
        create_table - 2026-06-09 17:23:12.048092+00:00
        add_weight - 2026-06-09 17:23:12.051249+00:00

      Pending:
        add_age

Stopping before a migration
===========================

When applying a single migration file, you can stop before a named migration:

.. code-block:: bash

    sqlite-utils migrate creatures.db path/to/migrations.py --stop-before add_weight

This applies any pending migrations before ``add_weight`` and leaves ``add_weight`` and later migrations pending.

Verbose output
==============

Use ``--verbose`` or ``-v`` to show the schema before and after migrations are applied, plus a unified diff when the schema changes:

.. code-block:: bash

    sqlite-utils migrate creatures.db --verbose

Migrating from sqlite-migrate
=============================

This system uses the same migration table format as the separate ``sqlite-migrate`` package. To use existing migration files directly with ``sqlite-utils``, update their import from ``sqlite_migrate`` to ``sqlite_utils``:

.. code-block:: python

    from sqlite_utils import Migrations

    migration = Migrations("creatures")

    @migration()
    def create_table(db):
        db["creatures"].create({"id": int, "name": str}, pk="id")

Python API
==========

.. autoclass:: sqlite_utils.migrations.Migrations
   :members:
   :undoc-members:
   :exclude-members: _Migration, _AppliedMigration