https://github.com/mdda/sqlalchemy-migrate-pylons

Simple script to migrate SQLalchemy databases used by Pylons
https://github.com/mdda/sqlalchemy-migrate-pylons

Last synced: 24 days ago
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Simple script to migrate SQLalchemy databases used by Pylons

• Host: GitHub
• URL: https://github.com/mdda/sqlalchemy-migrate-pylons
• Owner: mdda
• Created: 2010-09-15T18:11:11.000Z (over 15 years ago)
• Default Branch: master
• Last Pushed: 2011-05-15T21:54:36.000Z (about 15 years ago)
• Last Synced: 2025-12-28T19:05:38.111Z (6 months ago)
• Language: Python
• Homepage: http://platformedia.com/oss-blog/sqlalchemy-model-migration/
• Size: 102 KB
• Stars: 1
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.rst

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README

          
Stupidly simple SQLalchemy model migration

==========================================

This simple script pulls in the relavant database and model parameters from pylons .INI

It relies on the ``migrate`` egg for the ``diff`` and ``applyModel`` functions, and also makes use of the ConfigParser embedded in ``paste.deploy.loadwsgi``.

*It is most useful when rapidly developing / prototyping a Pylons application.*

Installation of required modules

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

easy_install SQLAlchemy

easy_install sqlalchemy-migrate

Setup of MYPROKJ .INI files and model meta files

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

1. Within the Pylons .INI file, it looks for a section called [app] *(the typical value is [app:main])*

2. The database URL is found from ``sqlalchemy.url`` :

    ``sqlalchemy.url = sqlite:///%(here)s/development.db``

3. The metadata for SQLalchemy is taken from a new entry : ``migrate.metadata`` :

    ``migrate.metadata = MYPROJ.model.meta:metadata``

 

 

Where the file MYPROJ/model/meta.py contains the following : ::

    from sqlalchemy import schema

    metadata = schema.MetaData()

    # The declarative DataBase base Object

    Base = declarative_base(metadata=metadata)

Syntax 

------

    (python-local) $ python sqlalchemy-migrate-pylons.py --help

    Usage: sqlalchemy-migrate-pylons.py [options] STANDALONE.ini 

    Options:

      -h, --help     show this help message and exit

      -a, --app      section to parse in ini file (default=app:main)

      -c, --commit   Use diffs to update database (default=False)

      -v, --verbose  Show debug messages

Normal usage

------------

1. To check what needs to be changed: 

    ``python sqlalchemy-migrate-pylons.py development.ini`` 

2. To implement the changes and report back:

    ``python sqlalchemy-migrate-pylons.py --commit development.ini`` 

Known Issues

------------

* Changing a model from ``nullable=True`` to ``nullable=False`` can be a problem, since the migrate package doesn't seem to understand ``default=''`` 

* The script is dependent on sqlalchemy-migrate, so could be incorporated into that package

* OTOH, it would probably sit better as a Paster-Pylons plug-in

* Please let me know if there are any other problems.

**As always : Back up your data before doing a migrate.**