Fetch data from multiple tables in django views - django

Question

In Django views, I want to fetch all details(Workeraccount.location,Workeravail.date, Workerprofile.*) for any particular wid=1.
SQL Query:
select * from Workeraccount,Workeravail,Workerprofile where Workerprofile.wid=1 and Workerprofile.wid=Workeravail.wid and Workeraccount.wid=Workerprofile.wid;
The corresponding models are as follows:
class Workeraccount(models.Model):
wid = models.ForeignKey('Workerprofile', db_column='wid', unique=True)
location = models.ForeignKey(Location, db_column='location')
class Meta:
managed = False
db_table = 'workerAccount'
class Workeravail(models.Model):
wid = models.ForeignKey('Workerprofile', db_column='wid')
date = models.DateField()
class Meta:
managed = False
db_table = 'workerAvail'
class Workerprofile(models.Model):
wid = models.SmallIntegerField(primary_key=True)
fname = models.CharField(max_length=30)
mname = models.CharField(max_length=30, blank=True, null=True)
lname = models.CharField(max_length=30)
gender = models.CharField(max_length=1)
age = models.IntegerField()
class Meta:
managed = False
db_table = 'workerProfile'`

Answer 1

You can do this:
workprofile = Workerprofile.objects.filter(id=1).first()
all_worker_avails = workprofile.workeravail_set.all()
all_workeraccounts = workprofile.workeraccount_set.all()
As Workeraccount and Workeravail are related through Workerprofile, you can get one queryset easily - you will need two separate ones.
You can also do the following:
all_worker_avails = Workeravail.objects.filter(wid=workprofile)
...

Answer 2

Here is how you can do it with only one database call:
workprofile = Workerprofile.objects.get(pk=1)
.select_related('workeravail_set', 'workerprofile_set')
This will fetch all the data for you at once, which can then be used with:
workprofile.workerprofile_set.location #Gets the Workeraccount.location
workprofile.workeravail_set.date #Gets the Workeravail.date
workprofile.fname #Example of Workerprofile.*
As an aside, if you want a shorter way to reference the foreign objects than the "*_set" method, you can set a related_name like
class Workeraccount(models.Model):
wid = models.ForeignKey('Workerprofile', db_column='wid', unique=True, related_name='waccount')
...
And then replace workeraccount_set with waccount