mirror of
https://github.com/django/django.git
synced 2024-12-25 10:35:48 +00:00
85ebb91846
model/field instance creation. Based on a patch from Richard Davies. git-svn-id: http://code.djangoproject.com/svn/django/trunk@8884 bcc190cf-cafb-0310-a4f2-bffc1f526a37
148 lines
4.5 KiB
Python
148 lines
4.5 KiB
Python
# -*- coding: utf-8 -*-
|
|
"""
|
|
14. Using a custom primary key
|
|
|
|
By default, Django adds an ``"id"`` field to each model. But you can override
|
|
this behavior by explicitly adding ``primary_key=True`` to a field.
|
|
"""
|
|
|
|
from django.conf import settings
|
|
from django.db import models, transaction, IntegrityError
|
|
|
|
class Employee(models.Model):
|
|
employee_code = models.IntegerField(primary_key=True, db_column = 'code')
|
|
first_name = models.CharField(max_length=20)
|
|
last_name = models.CharField(max_length=20)
|
|
class Meta:
|
|
ordering = ('last_name', 'first_name')
|
|
|
|
def __unicode__(self):
|
|
return u"%s %s" % (self.first_name, self.last_name)
|
|
|
|
class Business(models.Model):
|
|
name = models.CharField(max_length=20, primary_key=True)
|
|
employees = models.ManyToManyField(Employee)
|
|
class Meta:
|
|
verbose_name_plural = 'businesses'
|
|
|
|
def __unicode__(self):
|
|
return self.name
|
|
|
|
__test__ = {'API_TESTS':"""
|
|
>>> dan = Employee(employee_code=123, first_name='Dan', last_name='Jones')
|
|
>>> dan.save()
|
|
>>> Employee.objects.all()
|
|
[<Employee: Dan Jones>]
|
|
|
|
>>> fran = Employee(employee_code=456, first_name='Fran', last_name='Bones')
|
|
>>> fran.save()
|
|
>>> Employee.objects.all()
|
|
[<Employee: Fran Bones>, <Employee: Dan Jones>]
|
|
|
|
>>> Employee.objects.get(pk=123)
|
|
<Employee: Dan Jones>
|
|
>>> Employee.objects.get(pk=456)
|
|
<Employee: Fran Bones>
|
|
>>> Employee.objects.get(pk=42)
|
|
Traceback (most recent call last):
|
|
...
|
|
DoesNotExist: Employee matching query does not exist.
|
|
|
|
# Use the name of the primary key, rather than pk.
|
|
>>> Employee.objects.get(employee_code__exact=123)
|
|
<Employee: Dan Jones>
|
|
|
|
# pk can be used as a substitute for the primary key.
|
|
>>> Employee.objects.filter(pk__in=[123, 456])
|
|
[<Employee: Fran Bones>, <Employee: Dan Jones>]
|
|
|
|
# The primary key can be accessed via the pk property on the model.
|
|
>>> e = Employee.objects.get(pk=123)
|
|
>>> e.pk
|
|
123
|
|
|
|
# Or we can use the real attribute name for the primary key:
|
|
>>> e.employee_code
|
|
123
|
|
|
|
# Fran got married and changed her last name.
|
|
>>> fran = Employee.objects.get(pk=456)
|
|
>>> fran.last_name = 'Jones'
|
|
>>> fran.save()
|
|
>>> Employee.objects.filter(last_name__exact='Jones')
|
|
[<Employee: Dan Jones>, <Employee: Fran Jones>]
|
|
>>> emps = Employee.objects.in_bulk([123, 456])
|
|
>>> emps[123]
|
|
<Employee: Dan Jones>
|
|
|
|
>>> b = Business(name='Sears')
|
|
>>> b.save()
|
|
>>> b.employees.add(dan, fran)
|
|
>>> b.employees.all()
|
|
[<Employee: Dan Jones>, <Employee: Fran Jones>]
|
|
>>> fran.business_set.all()
|
|
[<Business: Sears>]
|
|
>>> Business.objects.in_bulk(['Sears'])
|
|
{u'Sears': <Business: Sears>}
|
|
|
|
>>> Business.objects.filter(name__exact='Sears')
|
|
[<Business: Sears>]
|
|
>>> Business.objects.filter(pk='Sears')
|
|
[<Business: Sears>]
|
|
|
|
# Queries across tables, involving primary key
|
|
>>> Employee.objects.filter(business__name__exact='Sears')
|
|
[<Employee: Dan Jones>, <Employee: Fran Jones>]
|
|
>>> Employee.objects.filter(business__pk='Sears')
|
|
[<Employee: Dan Jones>, <Employee: Fran Jones>]
|
|
|
|
>>> Business.objects.filter(employees__employee_code__exact=123)
|
|
[<Business: Sears>]
|
|
>>> Business.objects.filter(employees__pk=123)
|
|
[<Business: Sears>]
|
|
>>> Business.objects.filter(employees__first_name__startswith='Fran')
|
|
[<Business: Sears>]
|
|
|
|
# Primary key may be unicode string
|
|
>>> bus = Business(name=u'jaźń')
|
|
>>> bus.save()
|
|
|
|
# The primary key must also obviously be unique, so trying to create a new
|
|
# object with the same primary key will fail.
|
|
>>> try:
|
|
... sid = transaction.savepoint()
|
|
... Employee.objects.create(employee_code=123, first_name='Fred', last_name='Jones')
|
|
... transaction.savepoint_commit(sid)
|
|
... except Exception, e:
|
|
... if isinstance(e, IntegrityError):
|
|
... transaction.savepoint_rollback(sid)
|
|
... print "Pass"
|
|
... else:
|
|
... print "Fail with %s" % type(e)
|
|
Pass
|
|
|
|
"""}
|
|
|
|
# SQLite lets objects be saved with an empty primary key, even though an
|
|
# integer is expected. So we can't check for an error being raised in that case
|
|
# for SQLite. Remove it from the suite for this next bit.
|
|
if settings.DATABASE_ENGINE != 'sqlite3':
|
|
__test__["API_TESTS"] += """
|
|
# The primary key must be specified, so an error is raised if you try to create
|
|
# an object without it.
|
|
>>> try:
|
|
... sid = transaction.savepoint()
|
|
... Employee.objects.create(first_name='Tom', last_name='Smith')
|
|
... print 'hello'
|
|
... transaction.savepoint_commit(sid)
|
|
... print 'hello2'
|
|
... except Exception, e:
|
|
... if isinstance(e, IntegrityError):
|
|
... transaction.savepoint_rollback(sid)
|
|
... print "Pass"
|
|
... else:
|
|
... print "Fail with %s" % type(e)
|
|
Pass
|
|
|
|
"""
|