65 lines
1.9 KiB
Python
65 lines
1.9 KiB
Python
"""
|
|
33. get_or_create()
|
|
|
|
``get_or_create()`` does what it says: it tries to look up an object with the
|
|
given parameters. If an object isn't found, it creates one with the given
|
|
parameters.
|
|
"""
|
|
|
|
from django.db import models, IntegrityError
|
|
|
|
class Person(models.Model):
|
|
first_name = models.CharField(max_length=100)
|
|
last_name = models.CharField(max_length=100)
|
|
birthday = models.DateField()
|
|
|
|
def __unicode__(self):
|
|
return u'%s %s' % (self.first_name, self.last_name)
|
|
|
|
__test__ = {'API_TESTS':"""
|
|
# Acting as a divine being, create an Person.
|
|
>>> from datetime import date
|
|
>>> p = Person(first_name='John', last_name='Lennon', birthday=date(1940, 10, 9))
|
|
>>> p.save()
|
|
|
|
# Only one Person is in the database at this point.
|
|
>>> Person.objects.count()
|
|
1
|
|
|
|
# get_or_create() a person with similar first names.
|
|
>>> p, created = Person.objects.get_or_create(first_name='John', last_name='Lennon', defaults={'birthday': date(1940, 10, 9)})
|
|
|
|
# get_or_create() didn't have to create an object.
|
|
>>> created
|
|
False
|
|
|
|
# There's still only one Person in the database.
|
|
>>> Person.objects.count()
|
|
1
|
|
|
|
# get_or_create() a Person with a different name.
|
|
>>> p, created = Person.objects.get_or_create(first_name='George', last_name='Harrison', defaults={'birthday': date(1943, 2, 25)})
|
|
>>> created
|
|
True
|
|
>>> Person.objects.count()
|
|
2
|
|
|
|
# If we execute the exact same statement, it won't create a Person.
|
|
>>> p, created = Person.objects.get_or_create(first_name='George', last_name='Harrison', defaults={'birthday': date(1943, 2, 25)})
|
|
>>> created
|
|
False
|
|
>>> Person.objects.count()
|
|
2
|
|
|
|
# If you don't specify a value or default value for all required fields, you
|
|
# will get an error.
|
|
>>> try:
|
|
... p, created = Person.objects.get_or_create(first_name='Tom', last_name='Smith')
|
|
... except Exception, e:
|
|
... if isinstance(e, IntegrityError):
|
|
... print "Pass"
|
|
... else:
|
|
... print "Fail with %s" % type(e)
|
|
Pass
|
|
"""}
|