模型二

Posted 2020-08-31

基本的数据访问   直接上代码吧  比较简单的操作。

>>> from book.models import Publisher
>>> p1 = Publisher(name=‘Apress‘, address=‘2855 Telegraph Avenue‘,city=‘Berkeley‘, state_province=‘CA‘, country=‘U.S.A.‘,website=‘http://www.apress.com/‘)
>>> p1.save()
>>> p2 = Publisher(name="O‘Reilly", address=‘10 Fawcett St.‘,city=‘Cambridge‘, state_province=‘MA‘, country=‘U.S.A.‘,website=‘http://www.oreilly.com/‘)
>>> p2.save()
>>> publisher_list = Publisher.objects.all()
>>> publisher_list
<QuerySet [<Publisher: Publisher object>, <Publisher: Publisher object>]>
>>> type(publisher_list)
<class ‘django.db.models.query.QuerySet‘>
>>> for i in publisher_list:
...     i
... 
<Publisher: Publisher object>
<Publisher: Publisher object>
>>> for i in publisher_list:
...     i.name
... 
‘Apress‘
"O‘Reilly"
>>> Publisher.objects.create(name="O‘Yuqn", address=‘11 Fawcett St.‘,city=‘Cambridge‘, state_province=‘MA‘, country=‘U.S.A.‘,website=‘http://www.oreilly.com/‘)<Publisher: Publisher object>

>>> Publisher.objects.create(name="O‘Y11uqn", address=‘11 Fa11wcett St.‘,city=‘11Cambridge‘, state_province=‘11MA‘, country=‘U.111S.A.‘,website=‘http://www.orei11lly.com/‘)
<Publisher: Publisher object>
>>> publisher_list = Publisher.objects.all()
>>> for i in publisher_list:
...     i.name
... 
‘Apress‘
"O‘Reilly"
"O‘Yuqn"
"O‘Y11uqn"

如果我们要删除对象的话，删除数据库中的对象只需调用该对象的delete()方法即可：

>>> p = Publisher.objects.get(name="O‘Reilly")
>>> p.delete()
>>> Publisher.objects.filter(country=‘USA‘).delete()
>>> Publisher.objects.all().delete()

更新对象，很简单，先获取对象然后将其当做一般的变量进行赋值即可。当然还是要保存的。

>>> p.name = ‘Apress Publishing‘
>>> p.save()