Django模板外键遍历

Question

I saw multiple questions on this but non worked for me, so I'll query about my specific issue I have a table with several foreign keys pointing to other tables, looks like:

class EventCodes(models.Model):
    code_name = models.CharField(max_length=25)

class Severities(models.Model):
    severity_name = models.CharField(max_length=15)

class Systems(models.Model):
    system_id = models.CharField(max_length=15)

class Events(models.Model):
    system_id_fk = models.ForeignKey(Systems)
    severity_fk = models.ForeignKey(Severities)
    code_fk = models.ForeignKey(EventCodes)

I also have a template that allows a user to define a search criteria per system_id and/or severity_name and/or code_name -> this will give me the relevant records from the Events table

The only problem is that now when I present them in the results template I present their IDs and not their values (the Django ORM added the id PK for each of these tables)

QUESTION: How do i allow the results html which got the queryset of the Events to access the values on the System, Severities, EventCodes tables so I can present their string value and not their non human readable ID

Answer 1

You can span relationships by accessing the property by using . Django covers this in the documentation

an_event = Events.objects.all()[0]
an_event.system_id_fk.system_id

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Your naming convention could be a little confusing because for ForeignKey Fields django automatically creates an _id field on the model:

system_id_fk = models.ForeignKey(Systems)

The above creates a column named system_id_fk_id in the events table in your db. But when you access an_event.system_id_fk it will use the system_id_fk_id column to query the related objeCT!!!