aaugustin

"""Convert datetimes in the database when switching USE_TZ from False to True.

tl;dr RUNNING THIS SCRIPT CAN RESULT IN DATA CORRUPTION, DATA LOSS AND EVEN
      SERVER CRASHES. USE IT AT YOUR OWN RISK. NO WARRANTY WHATSOEVER.

This is a management command. Put it in the management.commands package of
one of your applications, then run: ./manage.py convert_to_utc <app_name> ...

This script assumes that no write operations take place while it's running.
It will rewrite every single record in your database; that's its whole point.

kalmbach

namespace :db do
  require "sequel"
  Sequel.extension :migration
  DB = Sequel.connect(ENV['DATABASE_URL'])
  
  desc "Prints current schema version"
  task :version do    
    version = if DB.tables.include?(:schema_info)
      DB[:schema_info].first[:version]
    end || 0

majackson

Django Migrations without Downtime

The following instructions describe a set of processes allowing you to run Django database migrations against a production database without having to bring the web service down.

Note that in the below instructions, migrations are all run manually at explicit points, and are not an automatic part of the deployment process.

Adding Fields or Tables

Adding a (nullable) field or a new table

1. Make the model or column addition in your code.

SpainTrain

from os import environ
from google.appengine.ext import ndb
from google.appengine.ext.ndb import model
from pydash import snake_case


class Config(ndb.Model):
    value = ndb.StringProperty()
    value_previous = ndb.StringProperty()