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POAtomic database operations in Django 1.4
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copied!<p>This question is similar to <a href="https://stackoverflow.com/questions/280075/atomic-operations-in-django">Atomic operations in Django?</a> however for Django 1.4. I'm wondering if there is a way to do this <em>without</em> resorting to "raw SQL". My setup is a little different then his so I'll explain.</p> <p>I have a record for a <em>User</em> and a generic table called <em>UserRecords</em>. Here's the definition for <em>UserRecord</em>.</p> <pre><code>class UserRecord (models.Model): """ User record model for :class:`User` users to keep aux data like services connected, latest stats, and other accounts. """ def __unicode__ (self): return u"{0}.{1}.{2}.{3}".format(self.user, self.parent, self.key, self.value) def update_maybe_save (self, val): if self.value != val: self.value = val self.save() #: :class`User` who owns this record user = models.ForeignKey("User") parent = models.CharField(max_length=255, blank=True, null=True, db_index=True) key = models.CharField(max_length=255, db_index=True) value = models.TextField(blank=True, null=True) </code></pre> <p>As you can see, it's a very generic k/v store table with the optional <em>parent</em> attribute that's useful for grouping records together and optimizing some searches. It's very useful when, in this case, we want to add a couple alias's for a user.</p> <pre><code># Inside the User model def add_alias (self, name): try: UserRecord.objects.get(user=self, parent="alias", key=name, value=self.username) except UserRecord.DoesNotExist: UserRecord(user=self, parent="alias", key=name, value=self.username).save() </code></pre> <p>This sets ourselves up for a race condition where if a user enters the same alias twice it could create two identical records. Then each <code>UserRecord.objects.get</code> call fails because there are two, I get a Django error email, and I manually go fix the database. </p> <p>I can't find anything in the documentation that allows me to create something atomically. Any ideas apart from the raw sql mentioned in the other question?</p>

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