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Snippets by cmgreen

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dumpdata/loaddata with MySQL and ForeignKeys

InnoDB tables within MySQL have no ability to defer reference checking until after a transaction is complete. This prevents most dumpdata/loaddata cycles unless the dump order falls so that referenced models are dumped before models that depend on them. This code uses [Ofer Faigon's](http://www.bitformation.com) topological sort to sort the models so that any models with a ForeignKey relationship are dumped after the models they reference. class Entry(models.Model): txt = .... class Comment(models.Model): entry = models.ForeignKey(Entry) This code will ensure that Entry always gets dumped before Comment. Fixtures are an important part of the django Unit Testing framework so I really needed to be able to test my more complicated models. **Caveats** 1. You use this snippet to dump the data and the built in manage.py loaddata to load the fixture output by this program. A similar solution could be applied to the XML processing on the loaddata side but this sufficed for my situations. 2. This code does not handle Circular or self-references. The loaddata for those needs to be much smarter.

  • mysql
  • loaddata
  • foreign-key
  • fixture
  • dumpdata
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dumpdata/loaddata with MySQL and ForeignKeys (Revision 2)

nnoDB tables within MySQL have no ability to defer reference checking until after a transaction is complete. This prevents most dumpdata/loaddata cycles unless the dump order falls so that referenced models are dumped before models that depend on them. This code uses Ofer Faigon's topological sort to sort the models so that any models with a ForeignKey relationship are dumped after the models they reference. class Entry(models.Model): txt = .... class Comment(models.Model): entry = models.ForeignKey(Entry) This code will ensure that Entry always gets dumped before Comment. Fixtures are an important part of the django Unit Testing framework so I really needed to be able to test my more complicated models. Caveats 1. You use this snippet to dump the data and the built in manage.py loaddata to load the fixture output by this program. A similar solution could be applied to the XML processing on the loaddata side but this sufficed for my situations. 2. This code does not handle Circular or self-references. The loaddata for those needs to be much smarter.

  • mysql
  • fixtures
  • dumpdata
Read More