django模板
模板查找顺序:
查找顺序
setting.py(INSTALL_APPS)顺序查找(APP)templates目录下的所有模板名字的字符串匹配(先全局,再局部),一旦匹配就不会再找
查找路径
完整路径:$APP/templates/user/login.html(从templates路径下算起)
from django.shortcuts import render
from django.views import View
from django.views.generic.base import TemplateView
class LoginView(View)
def get(self, request, *args, **kwargs):
retrun render(request, ‘test/login.html‘)
class LoginView(TemplateView):
template_name = "test/login.html"
django 模型
新建字段:
常用模型字段类型
注意:默认情况下Django会给每个模型添加下面这个字段id = models.AutoField(primary_key=True),如果Django看到你显式地设置了Field.primary_key, 就不会自动添加 id 列,每个模型只有一个字段指定primary_key=True
数据库迁移
迁移是Django同步您对模型所做更改(添加字段,删除模型等) 到您的数据库模式的方式
命令:
pyton manage.py [COMMAND]
migrate,负责应用和取消应用迁移。
makemigrations, 负责基于你的模型修改创建一个新的迁移
sqlmigrate, 展示迁移的sql语句
showmigrations,其中列出了项目的迁移及其状态。
##迁移指定app,生成迁移文件
[[email protected] cmdb-14]# python manage.py makemigrations webanalysis
Migrations for ‘webanalysis‘:
webanalysis/migrations/0002_idc.py
- Create model Idc
##展示迁移的sql语句
[[email protected] cmdb-14]# python manage.py sqlmigrate webanalysis 0002
##数据迁移
[[email protected] cmdb-14]# python manage.py migrate webanalysis
Operations to perform:
Apply all migrations: webanalysis
Running migrations:
Applying webanalysis.0002_idc... OK
注意:创建对象使用save(),或者使用create()方法
模型与数据库不一致的处理办法:
误删除迁移表,再次进行migration提示该表已存在
##误操作删除迁移表
select * from django_migrations;
14 | dashboard | 0001_initial | 2018-10-28 03:42:04
delete from django_migrations where id = 14;
##再次执行迁移
python manage.py migrate dashboard
#报错:django.db.utils.OperationalError: (1050, "Table ‘dashboard_idc‘ already exists")
##基于版本之间同步 强制执行 不执行数据库操作
python manage.py migrate dashboard --fake
模型里面有,数据库不一致
##先保证model.py与数据库一致
##删除迁移文件app/migrations/0001xxx
##删除数据库django_migrations下的迁移记录
##重新同步makemigrations migrate
delete from django_migrations where id >= 15;
python manage.py makemigrations dashboard
python manage.py migrate dashboard
执行查询
##导入模型
python manage.py shell
from [APP].models import [MODEL]
from django.contrib.auth.models import User,Group
>>> User.objects.all()
>>> User.objects.filter(name=‘xiaopf1‘).delete()
>>> User.objects.exclude(name=‘xiaopf1‘).update(name=‘xiaopf2‘)
>>> User.objects.filter(age__gt=10) #age>10 双下划线必须得加上
>>> User.objects.filter(age__gte=10) #age>=10
>>> User.objects.filter(age__lte=10)
>>> User.objects.filter(age__lt=10)
>>> User.objects.filter(name__contains=‘xiaopf‘)
>>> User.objects.filter(name__endswith=‘1‘)
>>> User.objects.filter(age__in=[10,11,12]).count()
>>> User.objects.filter(age__in=[10,11,12]).values(‘name‘,‘id‘)
>>> User.objects.order_by(‘age‘)
>>> User.objects.order_by(‘-age‘) #降序
>>> User.objects.order_by(‘age‘)[0]
>>> User.objects.order_by(‘age‘)[:3]
>>> User.objects.filter(name=‘xiaopf‘).update(addr=‘jieshou‘)
>>> User.objects.filter(name=‘xiaopf9‘).delete()
新增数据
##filter其他查询方法
###q.exclude/filter(body_text__icontains="food")
exact “精确”匹配
iexact 大小写不敏感的匹配
contains 大小写敏感的包含指定字符串
icontains 大小写不敏感的包含指定字符串
startswith, endswith 以指字字符串开头或结尾
istartswith, iendswith
in 在给定的列表内
##关系联系符
gt 大于
gte 大于或等于
lt 小于
lte 小于或等于
range 在指定范围内
filter()和get()区别
filter() 始终返回一个查询集,除非只有一个
只有一个对象满足你的查询,使用one_entry = Entry.objects.get(pk=1)
可以对get()使用任何查询表达式,和filter()一样
如果没有结果满足查询(单条),get()将引发一个Objects.DoesNotExist异常
如果多条满足get()查询条件,引发MultipleObjectsReturned异常
注意:使用from django.core.exceptions import ObjectDoesNotExist,MultipleObjectsReturned导入异常
序列化对象
将对象转换为可读的json格式serializers
from django.contrib.auth.models import User,Group
from django.core import serializers
class GroupListView(View):
‘‘‘
获取用组列表
‘‘‘
def get(self, request, *args, **kwargs):
queryset = Group.objects.all()
return HttpResponse(serializers.serialize("json", queryset), content_type="application/json")
django 模型关系
关系数据库的威力体现在表之间的相互关联。 Django 提供了三种最常见的数据库关系:多对一(many-to-one),多对多(many-to-many),一对一(one-to-one)
多对一Django 使用 django.db.models.ForeignKey 定义多对一关系,ForeignKey关联的模型是一,Foreignkey所在的模型是多
简单的例子: 比如,一辆Car有一个Manufacturer ,但是一个Manufacturer 生产很多汽车(Car),每一辆Car 只能有一个Manufacturer
class Car(models.Model):
name = models.CharField(‘名字‘,max_length=50,null=False,default=‘‘)
manufacturer=models.ForeignKey(Manufacturer)
class Manufacturer(models.Model):
name = models.CharField(‘名字‘,max_length=50,null=False,default=‘‘)
迁移,生产数据库
验证:
先有制造商,再有车吧,所以先新建制造商的对象
In [1]: from dashboard.models import Car,Manufacturer
In [2]: m1 = Manufacturer.objects.create(name=‘宝马‘)
In [3]: x1 = Car()
In [4]: x1.manufacturer = m1
In [5]: x1.name = ‘x1‘
In [6]: x1.save()
##正向查询,通过小汽车查询供应商(多对一)
In [8]: x1 = Car.objects.get(name=‘x1‘)
In [9]: x1.manufacturer.name
Out[9]: ‘宝马‘
##反向查询,通过供应商查询小汽车(一对多)
In [10]: m = Manufacturer.objects.get(name=‘宝马‘)
In [11]: m.car_set.all()
Out[11]: <QuerySet [<Car: Car object>]>
##修改小汽车关联供应商对象
In [50]: m1.name
Out[50]: ‘宝马‘
In [51]: m1.car_set.add(x1)
In [52]: x1.manufacturer.name
Out[52]: ‘宝马‘
In [53]: x1.name
Out[53]: ‘x1‘
删除:
In [54]: x1.delete()
Out[54]: (1, {‘dashboard.Car‘: 1})
注意:删除对象的时候先查看是否有关联,再删除数据,因为如果删除供应商,与之关联的小汽车也将被删除。
修改:
In [52]: x1.manufacturer.name
Out[52]: ‘宝马‘
In [53]: x1.name
Out[53]: ‘x1‘
In [54]: x1.delete()
Out[54]: (1, {‘dashboard.Car‘: 1})
In [55]: m2 = Manufacturer.objects.get(name=‘奥迪‘)
In [56]: x1.manufacturer = m2
In [57]: x1.name
Out[57]: ‘x1‘
In [58]: x1.manufacturer.name
Out[58]: ‘奥迪‘
多对多
ManyToManyField,其中一个models定义就行了,在哪个模型中定义并不重要
实例: 一个组对应多个人,一个人对应多个组
新增:
In [61]: from django.contrib.auth.models import Group,User
In [4]: Group.objects.create(name=‘admin‘)
In [4]: u = User.objects.get(username=‘user1‘)
In [5]: g1 = Group.objects.get(name=‘admin‘)
个人添加到组
In [6]: u.groups.add(g1)
In [7]: u.groups.all()
Out[7]: <QuerySet [<Group: admin>]>
组添加人:
In [11]: u2 = User.objects.get(username=‘user2‘)
In [12]: g1.user_set.add(u2)
In [13]: g1.user_set.all()
Out[13]: <QuerySet [<User: user1>, <User: user2>]>
个人删除组:
In [19]: u2.groups.all()
Out[19]: <QuerySet [<Group: admin>]>
In [20]: u2.groups.remove(g1)
In [21]: u2.groups.all()
Out[21]: <QuerySet []>
组删除个人:
In [26]: g1.user_set.all()
Out[26]: <QuerySet [<User: user2>]>
In [27]: g1.user_set.remove(u2)
In [28]: g1.user_set.all()
Out[28]: <QuerySet []>
彻底清空:
组:
In [48]: g2.user_set.all()
Out[48]: <QuerySet [<User: user1>, <User: user2>]>
In [49]:
In [49]: g2.user_set.clear()
In [50]: g2.user_set.all()
Out[50]: <QuerySet []>
个人:
In [57]: u.groups.all()
Out[57]: <QuerySet [<Group: wo>, <Group: admin>]>
In [58]: u.groups.clear()
In [59]: u.groups.all()
Out[59]: <QuerySet []>
重点:
使用serializers序列化对象为Json格式
from django.core import serializers
class GroupListView(View):
def get(self, request, *args, **kwargs):
queryset = Group.objects.all()
return HttpResponse(serializers.serialize("json", queryset), content_type="application/json")
Queryset对象或对象集不存在捕捉错误
from django.http import HttpResponse,Http404
from django.core.exceptions import ObjectDoesNotExist,MultipleObjectsReturned
class GroupUserView(View):
def get_group_obj(self):
try:
groupobj = Group.objects.get(name=self.request.GET.get(‘name‘))
except Group.DoesNotExist:
raise Http404
except Group.MultipleObjectsReturned:
raise Http404
return groupobj
class GroupMembers(View):
‘‘‘
获取用户组下的成员列表,参数为组名
‘‘‘
def get_group_members(self):
group_name = self.request.GET.get(‘name‘)
try:
groupobj = Group.objects.get(name=group_name)
except Group.DoesNotExist:
raise Http404
except Group.MultipleObjectsReturned:
raise Http404
get_group_members = groupobj.user_set.all()
return get_group_members
def get(self,request,*args,**kwargs):
queryset = self.get_group_members()
return HttpResponse(serializers.serialize(‘json‘, queryset), content_type="application/json")
class UserGroupList(View):
‘‘‘
获取用户组列表,参数为用户名
‘‘‘
def get_user_obj(self):
userobj = self.get_user()
return userobj.groups.all()
def get_user(self):
try:
userobj = User.objects.get(username=self.request.GET.get(‘username‘))
except User.DoesNotExist:
raise Http404
except User.MultipleObjectsReturned:
raise Http404
return userobj
def get(self,request,*args,**kwargs):
queryset = self.get_user_obj()
return HttpResponse(serializers.serialize(‘json‘, queryset), content_type="application/json")
from django.http import QueryDict
<QueryDict: {‘username‘: [‘user3‘], ‘groupname‘: [‘admin‘]}>
class GroupManage(View):
def get_group(self):
print(QueryDict(self.request.body))
try:
groupobj = Group.objects.get(name=QueryDict(self.request.body).get(‘groupname‘))
except Group.DoesNotExist:
raise Http404
except Group.MultipleObjectsReturned:
raise Http404
return groupobj
def user_group(self):
try:
userobj = User.objects.get(username=QueryDict(self.request.body).get(‘username‘))
except User.DoesNotExist:
raise Http404
except User.MultipleObjectsReturned:
raise Http404
return userobj
def delete(self,request,*args,**kwargs):
‘‘‘
将用户从用户组里删除
‘‘‘
userobj = self.user_group()
groupobj = self.get_group()
groupobj.user_set.remove(userobj)
return HttpResponse(‘用户已从用户组里删除‘)
def put(self,request,*args,**kwargs):
‘‘‘
将用户添加至用户组里
‘‘‘
userobj = self.user_group()
groupobj = self.get_group()
groupobj.user_set.add(userobj)
return HttpResponse(‘用户已添加至用户组‘)
验证:
In [46]: import requests
In [42]: data={‘username‘:‘user3‘,"groupname":‘admin‘}
In [43]: url="http://192.168.1.16:8000/dashboard/usergroupmanage/"
In [44]: r = requests.put(url,data=data)
In [45]: r.content.decode(‘utf8‘)
Out[45]: ‘用户已添加至用户组‘
In [73]: r = requests.delete(url,data=data)
In [74]: r.content.decode(‘utf8‘)
Out[74]: ‘用户已从用户组里删除
原文地址:http://blog.51cto.com/jacksoner/2315640