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POdjango queryset excluding entries in second model
 

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  1. POdjango queryset excluding entries in second model
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    <p>I'm making a little vocabulary-quiz app, and the basic model for a word is this:</p> <pre><code>class Word(models.Model): id = models.AutoField(primary_key=True) word = models.CharField(max_length=80) id_image = models.ForeignKey(Image) def __unicode__(self): return self.word class Meta: db_table = u'word' </code></pre> <p>The model for words I'm currently quizzing myself on is this:</p> <pre><code>class WordToWorkOn(models.Model): id = models.AutoField(primary_key=True) id_student = models.ForeignKey(Student) id_word = models.ForeignKey(Word) level = models.IntegerField() def __unicode__(self): return u'%s %s' % (self.id_word.__unicode__(), self.id_student.__unicode__() ) class Meta: db_table = u'word_to_work_on' </code></pre> <p>Where "level" indicates how well I've learned it. The set of words I've already learned has this model:</p> <pre><code>class WordLearned(models.Model): id = models.AutoField(primary_key=True) id_word = models.ForeignKey(Word, related_name='word_to_learn') id_student = models.ForeignKey(Student, related_name='student_learning_word') def __unicode__(self): return u'%s %s' % (self.id_word.__unicode__(), self.id_student.__unicode__() ) class Meta: db_table = u'word_learned' </code></pre> <p>When a queryset on WordToWorkOn comes back with too few results (because they have been learned well enough to get moved into WordLearned and deleted from WordToWorkOn), I want to find a Word to add to it. The part I don't know a good way to do is to limit it to Words which are not already in WordLearned.</p> <p>So, generally speaking, I think I want to do an .exclude() of some sort on a queryset of Words, but it needs to exclude based on membership in the WordLearned table. Is there a good way to do this? I find lots of references to joining querysets, but couldn't find a good one on how to do this (probably just don't know the right term to search for).</p> <p>I don't want to just use a flag on each Word to indicate learned, working on it, or not learned, because eventually this will be a multi-user app and I wouldn't want to have flags for every user. Hence, I thought multiple tables for each set would be better.</p> <p>All advice is appreciated.</p>
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