django数据库基本操作-增删改查（tip）-基本

1、插入数据

1 Python代码
2 >>> from books.models import Publisher
3 >>> p1 = Publisher(name=‘Apress‘, address=‘2855 Telegraph Avenue‘,
4 ...     city=‘Berkeley‘, state_province=‘CA‘, country=‘U.S.A.‘,
5 ...     website=‘http://www.apress.com/‘)
6 >>> p1.save()  

1 >>> from books.models import Publisher
2 >>> p1 = Publisher(name=‘Apress‘, address=‘2855 Telegraph Avenue‘,
3 ...     city=‘Berkeley‘, state_province=‘CA‘, country=‘U.S.A.‘,
4 ...     website=‘http://www.apress.com/‘)
5 >>> p1.save()  

2、查询

1 Python代码
2 >>> Publisher.objects.all()
3 [<Publisher: Apress>, <Publisher: O‘Reilly>]  

1 [python] view plain copy
2 >>> Publisher.objects.all()
3 [<Publisher: Apress>, <Publisher: O‘Reilly>]  

获取单个对象：

1 Python代码
2 >>> Publisher.objects.get(name="Apress")
3 <Publisher: Apress>  

1 [python] view plain copy
2 >>> Publisher.objects.get(name="Apress")
3 <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：

1 Python代码
2 >>> Publisher.objects.filter(name=‘Apress‘)
3 [<Publisher: Apress>] 

1 >>> Publisher.objects.filter(name=‘Apress‘)
2 [<Publisher: Apress>]  

1 Python代码
2 >>> Publisher.objects.filter(name__contains="press")
3 [<Publisher: Apress>]  

1 [python] view plain copy
2 >>> Publisher.objects.filter(name__contains="press")
3 [<Publisher: Apress>] 

__contains部分会被Django翻译成LIKE语句

排序：

1 Python代码
2 >>> Publisher.objects.order_by("name")
3 [<Publisher: Apress>, <Publisher: O‘Reilly>

1 python] view plain copy
2 >>> Publisher.objects.order_by("name")
3 [<Publisher: Apress>, <Publisher: O‘Reilly>]  

相当于 order by name asc

1 Python代码
2 >>> Publisher.objects.order_by("-name")  

1 [python] view plain copy
2 >>> Publisher.objects.order_by("-name") 

加个负号相当于 order by name desc

限制返回数据：

1 Python代码
2 >>> Publisher.objects.order_by(‘name‘)[0]
3 <Publisher: Apress>  

1 [python] view plain copy
2 >>> Publisher.objects.order_by(‘name‘)[0]
3 <Publisher: Apress>

相当于 limit 1

1 Python代码
2 >>> Publisher.objects.order_by(‘name‘)[0:2]  

1 [python] view plain copy
2 >>> Publisher.objects.order_by(‘name‘)[0:2]  

相当于 OFFSET 0 LIMIT 2

4、更新

1 Python代码
2 >>> Publisher.objects.filter(id=52).update(name=‘Apress Publishing‘)  

1 [python] view plain copy
2 >>> Publisher.objects.filter(id=52).update(name=‘Apress Publishing‘)  

1 Python代码
2 >>> p = Publisher.objects.get(name=‘Apress‘) #先查询
3 >>> p.name = ‘Apress Publishing‘ #更新
4 >>> p.save()  #保存  

1 [python] view plain copy
2 >>> p = Publisher.objects.get(name=‘Apress‘) #先查询
3 >>> p.name = ‘Apress Publishing‘ #更新
4 >>> p.save()  #保存  

5、删除

1 Python代码
2 >>> p = Publisher.objects.get(name="O‘Reilly")
3 >>> p.delete()  

1 [python] view plain copy
2 >>> p = Publisher.objects.get(name="O‘Reilly")
3 >>> p.delete()  

1 Python代码
2 >>> Publisher.objects.filter(country=‘USA‘).delete() 

1 [python] view plain copy
2 >>> Publisher.objects.filter(country=‘USA‘).delete()