101 lines
2.7 KiB
ReStructuredText
101 lines
2.7 KiB
ReStructuredText
dumpscript
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==========
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:synopsis: Generates a standalone Python script that will repopulate the database using objects.
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The `dumpscript` command generates a standalone Python script that will
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repopulate the database using objects. The advantage of this approach is that
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it is easy to understand, and more flexible than directly populating the
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database, or using XML.
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Why?
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----
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There are a few benefits to this:
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* less drama with model evolution: foreign keys handled naturally without IDs,
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new and removed columns are ignored
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* edit script to create 1,000s of generated entries using for loops, generated
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names, python modules etc.
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For example, an edited script can populate the database with test data::
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for i in xrange(2000):
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poll = Poll()
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poll.question = "Question #%d" % i
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poll.pub_date = date(2001,01,01) + timedelta(days=i)
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poll.save()
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Real databases will probably be bigger and more complicated, and so it is useful
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to enter some values using the admin interface and then edit the generated
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scripts.
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Features
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--------
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* *ForeignKey* and *ManyToManyFields* (using python variables, not object IDs)
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* Self-referencing *ForeignKey* (and M2M) fields
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* Sub-classed models
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* *ContentType* fields and generic relationships (but see issue 43)
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* Recursive references
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* *AutoFields* are excluded
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* Parent models are only included when no other child model links to it
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* Individual models can be referenced
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What it can't do (yet!)
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-----------------------
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* Ideal handling of generic relationships (ie no *AutoField* references):
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issue 43
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* Intermediate join tables: issue 48
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* GIS fields: issue 72
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How?
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----
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To dump the data from all the models in a given Django app (`appname`)::
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$ ./manage.py dumpscript appname > scripts/testdata.py
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To dump the data from just a single model (`appname.ModelName`)::
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$ ./manage.py dumpscript appname.ModelName > scripts/testdata.py
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To reset a given app, and reload with the saved data::
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$ ./manage.py reset appname
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$ ./manage.py runscript testdata
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Note: Runscript needs *scripts* to be a module, so create the directory and a
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*__init__.py* file.
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Caveats
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-------
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Naming conflicts
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~~~~~~~~~~~~~~~~
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Please take care that when naming the output files these filenames do not
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clash with other names in your import path. If for example the appname is
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the same as the script name then this can cause an importerror.
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Since instead of importing the application modules it tries to load the
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modules from the dumpscript file itself.
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Examples::
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# Wrong
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$ ./manage.py dumpscript appname > dumps/appname.py
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# Right
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$ ./manage.py dumpscript appname > dumps/appname_all.py
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# Right
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$ ./manage.py dumpscript appname.Somemodel > dumps/appname_somemodel.py
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