.. _backup:
    
======
Backup
======

You can make a Python dump of your database using the
:manage:`dump2py` :term:`django-admin command` that comes with Lino.
  
For example::
  
    $ python manage.py dump2py 20130117
    
This will create a directory `20130117` with a set of ` .py` files
which are a perfect representation, in Python, of your database at
that moment.  These files contain a complete backup of your database.
You can archive the directory and send it around per email.
  
  
To restore such a dump to your database, simply :manage:`run` the
:xfile:`restore.py` script from that directory::
  
      $ python manage.py run mydump/restore.py
  
Or, if you don't use per-project :xfile:`manage.py` files::
      
      $ set DJANGO_SETTINGS_MODULE=myproject
      $ django-admin.py run mydump/restore.py
  
Note that we are using here the :manage:`run` :term:`django-admin command`.
This makes it possible to restore your data into another project,
creating a copy of your database.
  


Note about `django-extensions <https://github.com/django-extensions>`_ 
----------------------------------------------------------------------

`django-extensions <https://github.com/django-extensions>`_ 
has a command "dumpscript" which is comparable to 
:mod:`dump2py <north.management.commands.dump2py>`.

The most important different is that the Python code 
generated by 
:mod:`dump2py <north.management.commands.dump2py>`
is designed in order to make it possible to 
write automated :ref:`database migrations <datamig>`.
  

Models that get special handling
--------------------------------

- `ContentType` objects aren't stored in a dump because they 
  can always be recreated.
- `Site` and `Permission` objects *must* be stored and *must not* be re-created
- `Session` objects can get lost in a dump and are not stored.