Migrations are a type of version control for databases, used to keep track of the changes made, and to provide easy maintainability. In case something goes wrong, 'rollback' can be run and it will revert the database to the previous state.
A migration consist in a Python script (preferably named by datetime of creation)
placed in the migrations directory.
The script should contain an import and a class called
Migration which implements
from limigrations.migration import BaseMigration class Migration(BaseMigration): def up(self, conn, c): pass def down(self, conn, c): pass
There is an example here.
Install the package with pip
$ pip install limigrations
or clone this repository and install
$ git clone email@example.com:dragosthealex/limigrations.git $ python setup.py install
1. In your project create a directory for migrations
$ mkdir my-migrations
2. Decide on a name for your database e.g. my-database.db
$ touch my-database.db
3. Create your first migration using the command-line, then edit the up and down methods
$ python -m limigrations new --new_migration "users_table" --migrations_dir "my-migrations"
Optionally, you can copy the example and modifying the up and down methods, saving it in your migrations directory. It's recommended to name it after the date and time e.g. 2017-03-08_12:31
$ python -m limigrations migrate --db_file "my-database.db" --migrations_dir "my-migrations"
5a. Done! You should now see the changes written in the up method being applied.
6a. If something goes wrong and you want to revert, run
$ python -m limigrations rollback --db_file "my-database.db" --migrations_dir "my-migrations"
7a. You should see the changes written in the down method being applied.
The following options can be used:
$ python -m limigrations -h usage: limigrations.py [-h] [-d DB_FILE] [-m MIGRATIONS_DIR] [-v] action positional arguments: action Action to take, can be 'migrate' or 'rollback' optional arguments: -h, --help show this help message and exit -d DB_FILE, --db_file DB_FILE Path to the database file. -m MIGRATIONS_DIR, --migrations_dir MIGRATIONS_DIR Path to the migrations directory. -v, --verbose Verbose
4b. Import the limigrations module and run the migrations
from limigrations import limigrations limigrations.migrate('my-database.db', 'my-migrations')
5a. If you want to rollback later, run the rollback
6a. If you just want to connect to the database
conn, c = limigrations.connect_database('my-database.db')
After cloning the repository, run
python -m unittest -v tests.test_limigrations
There are two tests, one for migrate and one for rollback. They create a test migration at runtime, defining the up and down methods, and then call the tested functions. The tests should leave no trace, as the directories and files are deleted after completion.
- Fork the repository on GitHub.
- Make a branch off of master and commit your changes to it.
- Run the tests with
- Ensure that your name is added to the end of the AUTHORS file using the
Name <firstname.lastname@example.org> (url), where the
(url)portion is optional.
- Submit a Pull Request to the master branch on GitHub.
If you'd like to have a development environment, you should create a
virtualenv and then do
pip install -e . from within the directory.
Alex Radu - initial work - www.alexdradu.com
This project is licensed under the MIT License - see the LICENSE.md file for details.