models for join django example

data2.py

ph2=Phone.objects.create(person=p1,area_code='770',number='1234567');

filter.py

Person.objects.filter(phone_set__area='770');

filter_distinct.py

Person.objects.filter(phone_set__area='770').distinct();

models.py

class Person(models.Model):
	name=models.CharField(max_length=20);
	def __unicode__(self):
		return self.name;
	
class Phone(models.Model):
	person=models.ForeignKey(Person);
	area_code=models.CharField(max_length=3);
	number=models.CharField(max_length=7);
	def __unicode__(self):
		return "("+self.area_code+")"+self.number +" for " +self.person.name;

output

In [8]: Person.objects.filter(phone__area_code='770')
Out[8]: [<Person: Orlando>, <Person: Orlando>]

In [9]: Person.objects.filter(phone__area_code='770').distinct()
Out[9]: [<Person: Orlando>]

sample data1.py

from joins.models import *;

p1=Person.objects.create(name='Orlando');
ph1=Phone.objects.create(person=p1,area_ code='770',number='1234567');

sql_in

SELECT *
FROM Person
WHERE id in (
   SELECT person_id
   FROM Phone
   WHERE area_code='770'
)

sql_join

SELECT Person.*
FROM Person JOIN Phone ON (Person.id=Phone.person_id)
WHERE Phone.area_code='770'