django数据库基本操作增删改查

9780j

1、插入数据


>>> from books.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()  

2、查询


>>> Publisher.objects.all()  
[<Publisher: Apress>, <Publisher: O'Reilly>]  
获取单个对象：


>>> Publisher.objects.get(name="Apress")  
<Publisher: Apress>  
如果结果是多个对象或者没有返回结果则会抛出异常

3、条件

筛选：

>>> Publisher.objects.filter(name='Apress')  
[<Publisher: Apress>]  


>>> Publisher.objects.filter(name__contains="press")  
[<Publisher: Apress>]  
__contains部分会被Django翻译成LIKE语句
排序：


>>> Publisher.objects.order_by("name")  
[<Publisher: Apress>, <Publisher: O'Reilly>]  
相当于 order by name asc

>>> Publisher.objects.order_by("-name")  
加个负号相当于 order by name desc

限制返回数据：


>>> Publisher.objects.order_by('name')[0]  
<Publisher: Apress>  
相当于 limit 1

>>> Publisher.objects.order_by('name')[0:2]  
相当于 OFFSET 0 LIMIT 2

4、更新


>>> Publisher.objects.filter(id=52).update(name='Apress Publishing')  


>>> p = Publisher.objects.get(name='Apress') #先查询  
>>> p.name = 'Apress Publishing' #更新  
>>> p.save()  #保存  

5、删除

>>> p = Publisher.objects.get(name="O'Reilly")  
>>> p.delete()  


>>> Publisher.objects.filter(country='USA').delete()