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PONewbie 1st atempt at prefetch_related - returns blank
 

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  1. PONewbie 1st atempt at prefetch_related - returns blank
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    <p>I asked this question before, but I received no solutions, so I have tried to make the question concise &amp; clearer this time.</p> <p>My database has the following simplified schema:</p> <pre><code>class RIAchievement(models.Model): riAchievementID = models.AutoField(primary_key=True, db_column="riAchievementID") userLanguageVersionID = models.ForeignKey(UserLanguageVersion, db_column="userLanguageVersionID", related_name="riAchievement_userLanguageVersionID") class Meta: db_table="riAchievement" class UserLanguageVersion(models.Model): userLanguageVersionID = models.AutoField(primary_key=True, db_column="userLanguageVersionID") languageCodeID = models.ForeignKey(LanguageCode, db_column="languageCodeID", related_name="userLanguageVersion_languageCodeID") class Meta: db_table="userLanguageVersion" class LanguageCode(models.Model): languagecodeID = models.AutoField(primary_key=True, db_column="languageCodeID") class Meta: db_table="languageCode" class Flag(models.Model): flagID = models.AutoField(primary_key=True, db_column="flagID") languageCodeID = models.ForeignKey(LanguageCode, db_column="languageCodeID", related_name="flag_languageCodeID") flagIconPath = models.CharField(max_length=255, db_column="flagIconPath") class Meta: db_table="flag" </code></pre> <p>Essentially, riachievement can have many userlanguageversion s and userlanguageversion can have many languagecode s, and flag can have many languagecode s.</p> <p>Using <strong>select_related</strong> does not return <em>flag.flagIconPath</em> because of the 1 to many relationship, so the Django docs state I must use <strong>prefetch_related</strong>, with the <strong>related name</strong> of the 1 to many foreign key.</p> <p>So I amend my code in my <strong>view.py</strong>:</p> <pre><code>from django.shortcuts import render from app_data.models import RIAchievement def ri_achievements(request): qs = RIAchievement.objects.select_related("riachievement", "userlanguageversion", "languagecode", "flag_languageCodeID").all() return render(request, 'index.html',{'qs': qs}) </code></pre> <p>And my <strong>index.html</strong>:</p> <pre><code>{% for ri_achievement in qs %} {{ ri_achievement.userLanguageVersionID.langaugeCodeID.flag_languageCodeID.flagIconPath }} {% endfor %} </code></pre> <p>But, this code returns nothing.</p> <p>Can anyone offer some advice, as I cannot see what I have done wrong?</p>
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    1. USuser1261774
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