Added Manager.get_or_create()

git-svn-id: http://code.djangoproject.com/svn/django/trunk@3092 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/modeltests/get_or_create/models.py

@@ -0,0 +1,52 @@
+"""
+32. 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
+
+class Person(models.Model):
+    first_name = models.CharField(maxlength=100)
+    last_name = models.CharField(maxlength=100)
+    birthday = models.DateField()
+
+    def __str__(self):
+        return '%s %s' % (self.first_name, self.last_name)
+
+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
+"""