dumpscript

synopsis:Generates a standalone Python script that will repopulate the database using objects.

The dumpscript command generates a standalone Python script that will repopulate the database using objects. The advantage of this approach is that it is easy to understand, and more flexible than directly populating the database, or using XML.

Why?

There are a few benefits to this:

  • less drama with model evolution: foreign keys handled naturally without IDs, new and removed columns are ignored
  • edit script to create 1,000s of generated entries using for loops, generated names, python modules etc.

For example, an edited script can populate the database with test data:

for i in xrange(2000):
    poll = Poll()
    poll.question = "Question #%d" % i
    poll.pub_date = date(2001,01,01) + timedelta(days=i)
    poll.save()

Real databases will probably be bigger and more complicated so it is useful to enter some values using the admin interface and then edit the generated scripts.

Features

  • ForeignKey and ManyToManyFields (using python variables, not object IDs)
  • Self-referencing ForeignKey (and M2M) fields
  • Sub-classed models
  • ContentType fields and generic relationships (but see issue 43)
  • Recursive references
  • AutoFields are excluded
  • Parent models are only included when no other child model links to it
  • Individual models can be referenced

What it can’t do (yet!)

  • Ideal handling of generic relationships (ie no AutoField references): issue 43
  • Intermediate join tables: issue 48
  • GIS fields: issue 72

How?

To dump the data from all the models in a given Django app (appname):

$ ./manage.py dumpscript appname > scripts/testdata.py

To dump the data from just a single model (appname.ModelName):

$ ./manage.py dumpscript appname.ModelName > scripts/testdata.py

To reset a given app, and reload with the saved data:

$ ./manage.py reset appname
$ ./manage.py runscript testdata

Note: Runscript needs scripts to be a module, so create the directory and a __init__.py file.

Caveats

Naming conflicts

Please take care that when naming the output files these filenames do not clash with other names in your import path. For instance, if the appname is the same as the script name, an importerror can occur because rather than importing the application modules it tries to load the modules from the dumpscript file itself.

Examples:

# Wrong
$ ./manage.py dumpscript appname > dumps/appname.py

# Right
$ ./manage.py dumpscript appname > dumps/appname_all.py

# Right
$ ./manage.py dumpscript appname.Somemodel > dumps/appname_somemodel.py