Django-tables2 reverse lookup

Question

I have a table that displays a list of "leads" which are rendered fine. There is also a related model which is called "Leadupdate" that is related to "lead" model that is used in the table. There is a many to one relationship from Leadupdate to lead with a foreign key. I want to display all the related updates for the individual "leads" in one of the updates column. There are several examples online for following forward relationship through foreign key but haven't found one for reverse yet. Here is one example of said relationship Accessor forward look up.

EDIT: Look up will be done on a Django-tables2 module instance table. I am not asking reverse look up on a model but doing it in context of Django-tables2.

Models.py:

    class lead(models.Model):
        slug = models.SlugField(unique=True,blank=True, null=True)
        first_name = models.CharField(max_length=100)
        last_name = models.CharField(max_length=100, blank=True, null=True)
        business_name = models.CharField(max_length=100,blank=True, null=True)
        email = models.EmailField(max_length=75, blank=True, null=True)
        phone_number = models.CharField(max_length=20, blank=True, null=True)
        address = models.CharField(max_length=150, blank=True, null=True)
        city = models.CharField(max_length=50, blank=True, null=True)
        state = models.CharField(max_length=10, blank=True, null=True) 
        zipcode = models.CharField(max_length=5, blank=True, null=True)
        submission_date = models.DateTimeField(auto_now_add=True, blank=True)
        assigned_to = models.ManyToManyField(Listing,blank=True, null=True, related_name="leads")
        requested_software = models.CharField(max_length=50, blank=True, null=True)
        type_of_business = models.CharField(max_length=30, choices=TYPE_OF_BUSINESS, default='Bar', blank=True, null=True) 
        time_frame = models.CharField(max_length=10, choices=TIME_FRAME, default='1')
        comments = models.TextField(blank=True, null=True)

        def __unicode__(self):
            return self.business_name
        @models.permalink
        def get_absolute_url(self):
            return('listing_detail', (),{'slug' :self.slug,})

        def save(self, *args, **kwargs):
            if not self.slug:
                self.slug = slugify(self.business_name)
                super(lead, self).save(*args, **kwargs)


class Leadupdate(models.Model):

    CONFIDENCE_LEVEL = (
            ('HOT', 'HOT'),
            ('COLD', 'COLD'),
            )

    LEAD_VALUE = (
            ('1K3K', '1K-3K'),
            ('5K10K', '5K-10K'),
            ('10K20K', '10K-20K'),
            ('20K50K', '20K-50K'),
            ('50KUP', '5OK-UP'),
            )

    ESTIMATED_CLOSING = (
            ('1w4w', '1-4 Weeks'),
            ('1m3m', '1-3 Months'),
            ('3m6m', '3-6 Months'),
            ('6m+', '6+ Months'),
            )

    updatedate = models.DateTimeField(auto_now_add=True)
    update = models.TextField(blank=True, null=True)
    updatefrom = models.ForeignKey(Listing, related_name="update_from", blank=True, null=True)
    lead = models.ForeignKey(lead, related_name="related_update",blank=True, null=True)
    lead_confidence_level = models.CharField(max_length=10, choices=CONFIDENCE_LEVEL, default='COLD', blank=True, null=True)
    estimated_lead_value  = models.CharField(max_length=10, choices=LEAD_VALUE, default='1K3K', blank=True, null=True)
    estimated_closing_frame  = models.CharField(max_length=10, choices=ESTIMATED_CLOSING, default='1-4 Weeks', blank=True, null=True)
    def __unicode__(self):
        return u" %s - %s " % (self.update, self.updatedate)

Table:

class LeadTable(tables.Table):
    business_name = tables.LinkColumn('lead-detail', args=[A('slug')])
    updates = tables.Column(accessor='lead.related_update')
    class Meta:
        model = lead
        fields = ("business_name","first_name", "last_name","number_of_pos","submission_date","updates")
        attrs = {"class":"paleblue"}

In order to explain your problem more clearly you could mention that there exists a module named django-tables2 and provide a minimal example with something like 5 lines of code. — Philipp Zedler

Steve Steve · Accepted Answer · 2016-01-24T06:12:05

A late answer, but here is what works for me in Django 1.8.6 with django-tables2 1.1.0 (based on Django-Tables2 Issue 156 and This answer). To access a one to many set of objects via a foreign key relation you need to just use the related_name in the accessor and then create a render method to produce what gets written to column cell. In that method you can then get all the foreign model objects and access their fields in a for loop.

class LeadTable(tables.Table):
    business_name = tables.LinkColumn('lead-detail', args=[A('slug')])
    updates = tables.Column(accessor='related_update')
    def render_updates(self, value, table):
        updates = ""
        uFirst = True
        updatesList = list(value.all())
        for u in updatesList:
            if not uFirst:
                updates += ", "
            else:
                uFirst = False
            updates += u.update
        return updates
    class Meta:
        model = lead
        fields = ("business_name","first_name", "last_name","number_of_pos","submission_date","updates")
        attrs = {"class":"paleblue"}

Django-tables2 reverse lookup

2 Answers