tiny-migrations 0.1.2

A tiny, lightweight, package for managing database migrations. Designed to work without INI files or dynamic module loading, making it ideal for compiled or frozen applications as well as traditional servers.

Tiny Migrations

Introdution

A tiny, lightweight, package for managing sqlite database migrations. Designed to work without INI files or dynamic module loading, making it ideal for compiled or frozen applications as well as traditional servers.

• PyPI package: https://pypi.org/project/tiny-migrations/
• Free software: MIT License

Installation

Install via pip:

pip install tiny-migrations

---

Defining Migrations

Create migration classes by subclassing MigrationBase. Each migration must implement the up(db_connection) method.

from tiny_migrations import MigrationBase

class CreateUsersTable(MigrationBase):
    def up(self, db_connection):
        cursor = db_connection.cursor()
        cursor.execute("""
            CREATE TABLE users (
                id INTEGER PRIMARY KEY,
                username TEXT NOT NULL
            );
        """)
        db_connection.commit()
        cursor.close()

Each migration requires a unique ID and a description:

migration1 = CreateUsersTable("001", "Create users table")

You can specify dependencies using the depends_on argument:

migration2 = AddEmailColumn("002", "Add email column", depends_on=migration1)

---

Setting Up the Database Connection

Use a direct sqlite3.Connection object:

import sqlite3

db_conn = sqlite3.connect("my_database.db")

---

Running Migrations

Pass your migrations to TinyMigrations and run them in order:

from tiny_migrations import TinyMigrations

tm = TinyMigrations(db_conn)
tm.migrate([migration1, migration2])

---

Migration Dependencies

Migrations must depend on a previous migration. Ensure you pass them in dependency order:

migration2 = AddEmailColumn("002", "Add email column", depends_on=migration1)
tm.migrate([migration1, migration2])

---

Targeted Migration

You can migrate up to a specific migration by passing its unique ID:

tm.migrate([migration1, migration2, migration3], target_migration="002")

---

Example: Adding and Modifying Tables

class AddAgeColumn(MigrationBase):
    def up(self, db_connection):
        cursor = db_connection.cursor()
        cursor.execute("ALTER TABLE users ADD COLUMN age INTEGER;")
        db_connection.commit()
        cursor.close()

migration3 = AddAgeColumn("003", "Add age column", depends_on=migration2)

tm.migrate([migration1, migration2, migration3])

---

Stamping Migrations

You can mark a migration as applied without actually running its up method using the stamp feature. This is useful when you want to record that a migration has already been applied manually or outside of Tiny Migrations.

tm.stamp("001", "Stamp test migration")

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Troubleshooting

• If you get a dependency error, check the order and depends_on attributes.
• Make sure your up method receives the database connection argument.