运维开发笔记整理-数据分页

　　　　　　　　　　　　运维开发笔记整理-数据分页

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　作者：尹正杰 

版权声明：原创作品，谢绝转载！否则将追究法律责任。

 

 

一.创建测试数据（批量创建1000个用户）

C:\Users\yinzhengjie\softwares\GitHub\DevOps>python manage.py shell
Python 3.6.0 (v3.6.0:41df79263a11, Dec 23 2016, 08:06:12) [MSC v.1900 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>>

C:\Users\yinzhengjie\softwares\GitHub\DevOps>python manage.py shell
Python 3.6.0 (v3.6.0:41df79263a11, Dec 23 2016, 08:06:12) [MSC v.1900 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>>
>>> from django.contrib.auth.models import User
>>>
>>> username = "yinzhengjie"
>>>
>>> for i in range(1000):
...  name = "{}_{}".format(username,i)
...  User.objects.create_user(name,"{}@yinzhengjie.org.cn".format(name),"123")
...
<User: yinzhengjie_0>
<User: yinzhengjie_1>
<User: yinzhengjie_2>
<User: yinzhengjie_3>
<User: yinzhengjie_4>
<User: yinzhengjie_5>
<User: yinzhengjie_6>
<User: yinzhengjie_7>
<User: yinzhengjie_8>
<User: yinzhengjie_9>
<User: yinzhengjie_10>
<User: yinzhengjie_11>
<User: yinzhengjie_12>
<User: yinzhengjie_13>
<User: yinzhengjie_14>
<User: yinzhengjie_15>
<User: yinzhengjie_16>
<User: yinzhengjie_17>
<User: yinzhengjie_18>
<User: yinzhengjie_19>
<User: yinzhengjie_20>
<User: yinzhengjie_21>
<User: yinzhengjie_22>
<User: yinzhengjie_23>
........

>>> User.objects.all()
<QuerySet [<User: yinzhengjie>, <User: admin>, <User: chenfei>, <User: jenny>, <User: yinzhengjie_0>, <User: yinzhengjie_1>, <User: yinzhengjie_2>, <User: yinzhengjie_3>, <User: yinzhengjie_4>, <User: yinzhengjie_5>, <User: yinzhengjie_6>, <User: yinzhengjie_7>, <User: yinzhengjie_8>, <User: yinzhengjie
_9>, <User: yinzhengjie_10>, <User: yinzhengjie_11>, <User: yinzhengjie_12>, <User: yinzhengjie_13>, <User: yinzhengjie_14>, <User: yinzhengjie_15>, '...(remaining elements truncated)...']>
>>>

>>> User.objects.all()[:10]
<QuerySet [<User: yinzhengjie>, <User: admin>, <User: chenfei>, <User: jenny>, <User: yinzhengjie_0>, <User: yinzhengjie_1>, <User: yinzhengjie_2>, <User: yinzhengjie_3>, <User: yinzhengjie_4>, <User: yinzhengjie_5>]>
>>>

>>> queryset = User.objects.all()[:10]
>>>
>>> queryset.values()
<QuerySet [{'id': 1, 'password': 'pbkdf2_sha256$36000$mpkI6GLbFQxO$92QgD28jd838LlgzTsnFsvw+2CbTAgK+LgzS3G40h/k=', 'last_login': datetime.datetime(2019, 1, 14, 8, 7, 20, tzinfo=<UTC>), 'is_superuser': False, 'username': 'yinzhengjie', 'first_name': '', 'last_name': '', 'email': 'yinzhengjie@yinzhengjie.o
rg.cn', 'is_staff': False, 'is_active': True, 'date_joined': datetime.datetime(2019, 1, 9, 13, 3, 26, tzinfo=<UTC>)}, {'id': 2, 'password': 'pbkdf2_sha256$36000$AJNnOcpMRfAB$wvsTcO221K9c/ogSIW8WuK4ti4iRbVp6LliFJnq0PlA=', 'last_login': None, 'is_superuser': True, 'username': 'admin', 'first_name': '', 'l
ast_name': '', 'email': 'admin@yinzhengjie.org.cn', 'is_staff': True, 'is_active': True, 'date_joined': datetime.datetime(2019, 1, 9, 13, 7, 43, tzinfo=<UTC>)}, {'id': 3, 'password': 'pbkdf2_sha256$36000$9xEXixjbrwgW$VRE2gdFRjnI6E3mc4nor3rUqBP97wai8xqulzgRnwPQ=', 'last_login': datetime.datetime(2019, 1,
 11, 9, 54, 22, tzinfo=<UTC>), 'is_superuser': False, 'username': 'chenfei', 'first_name': '', 'last_name': '', 'email': 'chenfei@yinzhengjie.org.cn', 'is_staff': False, 'is_active': True, 'date_joined': datetime.datetime(2019, 1, 11, 9, 24, 6, tzinfo=<UTC>)}, {'id': 4, 'password': 'pbkdf2_sha256$36000$
Frpw9hmKTaKa$B4dVdqiM4K+2yFLd3DfQV74mv2tllwnZxjJPFjhEh2A=', 'last_login': datetime.datetime(2019, 1, 11, 9, 35, 32, tzinfo=<UTC>), 'is_superuser': True, 'username': 'jenny', 'first_name': '', 'last_name': '', 'email': '', 'is_staff': True, 'is_active': True, 'date_joined': datetime.datetime(2019, 1, 11,
 9, 35, 17, tzinfo=<UTC>)}, {'id': 5, 'password': 'pbkdf2_sha256$36000$Igzct2aN2kIn$KJUA3qbjZYT8Mz8UubgptT425CrAZI3lr1L47tOYnKA=', 'last_login': None, 'is_superuser': False, 'username': 'yinzhengjie_0', 'first_name': '', 'last_name': '', 'email': 'yinzhengjie_0@yinzhengjie.org.cn', 'is_staff': False, 'i
s_active': True, 'date_joined': datetime.datetime(2019, 1, 15, 6, 39, 47, tzinfo=<UTC>)}, {'id': 6, 'password': 'pbkdf2_sha256$36000$pVgOfvV7xnLA$v/HdnmOrON5yXQm6Tu/ESQLExwzsDLS1HYmB420STw0=', 'last_login': None, 'is_superuser': False, 'username': 'yinzhengjie_1', 'first_name': '', 'last_name': '', 'ema
il': 'yinzhengjie_1@yinzhengjie.org.cn', 'is_staff': False, 'is_active': True, 'date_joined': datetime.datetime(2019, 1, 15, 6, 39, 47, tzinfo=<UTC>)}, {'id': 7, 'password': 'pbkdf2_sha256$36000$AcBse0DrqytQ$UDTl3i8wozYnEcRCanRcTxF06sQCdW4ezDNDDOBW6Iw=', 'last_login': None, 'is_superuser': False, 'usern
ame': 'yinzhengjie_2', 'first_name': '', 'last_name': '', 'email': 'yinzhengjie_2@yinzhengjie.org.cn', 'is_staff': False, 'is_active': True, 'date_joined': datetime.datetime(2019, 1, 15, 6, 39, 47, tzinfo=<UTC>)}, {'id': 8, 'password': 'pbkdf2_sha256$36000$hkSzLweU5YB1$TNwHHuQ3X+4s2bw31yLc1oxYfo+2OhE0CR
FQrZi6QtA=', 'last_login': None, 'is_superuser': False, 'username': 'yinzhengjie_3', 'first_name': '', 'last_name': '', 'email': 'yinzhengjie_3@yinzhengjie.org.cn', 'is_staff': False, 'is_active': True, 'date_joined': datetime.datetime(2019, 1, 15, 6, 39, 47, tzinfo=<UTC>)}, {'id': 9, 'password': 'pbkdf
2_sha256$36000$9MCEySYs7ioI$XlA3AAUeOYY+IbGEREQTLMEHyulzcenEDRgKTzUlUns=', 'last_login': None, 'is_superuser': False, 'username': 'yinzhengjie_4', 'first_name': '', 'last_name': '', 'email': 'yinzhengjie_4@yinzhengjie.org.cn', 'is_staff': False, 'is_active': True, 'date_joined': datetime.datetime(2019,
1, 15, 6, 39, 47, tzinfo=<UTC>)}, {'id': 10, 'password': 'pbkdf2_sha256$36000$LWtenjjciVrx$OY49hPmpRJwqrxtyb16MY8vbWz9tZtgqUiF72obodyQ=', 'last_login': None, 'is_superuser': False, 'username': 'yinzhengjie_5', 'first_name': '', 'last_name': '', 'email': 'yinzhengjie_5@yinzhengjie.org.cn', 'is_staff': Fa
lse, 'is_active': True, 'date_joined': datetime.datetime(2019, 1, 15, 6, 39, 47, tzinfo=<UTC>)}]>
>>>

 

C:\Users\yinzhengjie\softwares\GitHub\DevOps>python manage.py shell
Python 3.6.0 (v3.6.0:41df79263a11, Dec 23 2016, 08:06:12) [MSC v.1900 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>>
>>> from django.contrib.auth.models import User
>>>
>>> queryset = User.objects.all()[:10]
>>>
>>> queryset.values("username","email")
<QuerySet [{'username': 'yinzhengjie', 'email': 'yinzhengjie@yinzhengjie.org.cn'}, {'username': 'admin', 'email': 'admin@yinzhengjie.org.cn'}, {'username': 'chenfei', 'email': 'chenfei@yinzhengjie.org.cn'}, {'username': 'jenny', 'email': ''}, {'username': 'yinzhengjie_0', 'email': 'yinzhengjie_0@yinzhen
gjie.org.cn'}, {'username': 'yinzhengjie_1', 'email': 'yinzhengjie_1@yinzhengjie.org.cn'}, {'username': 'yinzhengjie_2', 'email': 'yinzhengjie_2@yinzhengjie.org.cn'}, {'username': 'yinzhengjie_3', 'email': 'yinzhengjie_3@yinzhengjie.org.cn'}, {'username': 'yinzhengjie_4', 'email': 'yinzhengjie_4@yinzhen
gjie.org.cn'}, {'username': 'yinzhengjie_5', 'email': 'yinzhengjie_5@yinzhengjie.org.cn'}]>
>>>

C:\Users\yinzhengjie\softwares\GitHub\DevOps>python manage.py shell
Python 3.6.0 (v3.6.0:41df79263a11, Dec 23 2016, 08:06:12) [MSC v.1900 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>>
>>> from django.contrib.auth.models import User
>>>
>>> queryset = User.objects.all()[:10]
>>>
>>> queryset.values("username","email")
<QuerySet [{'username': 'yinzhengjie', 'email': 'yinzhengjie@yinzhengjie.org.cn'}, {'username': 'admin', 'email': 'admin@yinzhengjie.org.cn'}, {'username': 'chenfei', 'email': 'chenfei@yinzhengjie.org.cn'}, {'username': 'jenny', 'email': ''}, {'username': 'yinzhengjie_0', 'email': 'yinzhengjie_0@yinzhen
gjie.org.cn'}, {'username': 'yinzhengjie_1', 'email': 'yinzhengjie_1@yinzhengjie.org.cn'}, {'username': 'yinzhengjie_2', 'email': 'yinzhengjie_2@yinzhengjie.org.cn'}, {'username': 'yinzhengjie_3', 'email': 'yinzhengjie_3@yinzhengjie.org.cn'}, {'username': 'yinzhengjie_4', 'email': 'yinzhengjie_4@yinzhen
gjie.org.cn'}, {'username': 'yinzhengjie_5', 'email': 'yinzhengjie_5@yinzhengjie.org.cn'}]>
>>>
>>> list(queryset.values("username","email"))
[{'username': 'yinzhengjie', 'email': 'yinzhengjie@yinzhengjie.org.cn'}, {'username': 'admin', 'email': 'admin@yinzhengjie.org.cn'}, {'username': 'chenfei', 'email': 'chenfei@yinzhengjie.org.cn'}, {'username': 'jenny', 'email': ''}, {'username': 'yinzhengjie_0', 'email': 'yinzhengjie_0@yinzhengjie.org.c
n'}, {'username': 'yinzhengjie_1', 'email': 'yinzhengjie_1@yinzhengjie.org.cn'}, {'username': 'yinzhengjie_2', 'email': 'yinzhengjie_2@yinzhengjie.org.cn'}, {'username': 'yinzhengjie_3', 'email': 'yinzhengjie_3@yinzhengjie.org.cn'}, {'username': 'yinzhengjie_4', 'email': 'yinzhengjie_4@yinzhengjie.org.c
n'}, {'username': 'yinzhengjie_5', 'email': 'yinzhengjie_5@yinzhengjie.org.cn'}]
>>>

 

二.文档浏览器（mac和windows文档）

1>.window登录官网（https://devdocs.io）

2>.mac文档（https://kapeli.com/dash） 

　　该文档需要授权，因为它是收费的。 

　　关于paginator的文档，详情请参考：https://devdocs.io/django~1.11/topics/pagination#django.core.paginator.Paginator 。

　　关于page的文档，详情请参考：https://devdocs.io/django~1.11/topics/pagination#django.core.paginator.Page。

 　

三.数据分页原理案例

 　　dashboard的url.py配置文件，如下图所示：

#！/usr/bin/env python
#_*_conding:utf-8_*_
#@author :yinzhengjie
#blog:http://www.cnblogs.com/yinzhengjie/tag/python%E8%87%AA%E5%8A%A8%E5%8C%96%E8%BF%90%E7%BB%B4%E4%B9%8B%E8%B7%AF/

from django.conf.urls import url
from . import  views

urlpatterns = [
    url(r"^login/",views.LoginView.as_view()),
    url(r"^index/", views.MyPageView.as_view()),
]

　　编写对应的views.py配置文件：

#！/usr/bin/env python
#_*_conding:utf-8_*_
#@author :yinzhengjie
#blog:http://www.cnblogs.com/yinzhengjie/tag/python%E8%87%AA%E5%8A%A8%E5%8C%96%E8%BF%90%E7%BB%B4%E4%B9%8B%E8%B7%AF/

from django.http import HttpResponse,JsonResponse
from django.shortcuts import  render
from django.views import View
from django.contrib.auth.models import User

class LoginView(View):

    def get(self,request):
        return render(request,"login.html")

    def post(self,request):
        print("调用了POST方法！")
        return HttpResponse("post...")



class MyPageView(View):
    def get(self,request,*args,**kwargs):
        #定义每个页码显示信息的条数
        Number_of_per_page = 10
        try:
            #获取到用户传递过来的查询页码
            page = int(request.GET.get("page",1))
        except:
            #如果用户没有传递要查询的页码，我们这里给其设置一个默认值1，即显示第一页。
            page = 1

        #定义查询的起始位置
        end = page * 10
        start = end - 10

        #定义查询的语句，注意这里并没有去数据库直接查询语句，这里只是定义好了要查询的SQL语句
        queryset =  User.objects.all()[start:end]

        #触发SQL语句，并将查询的结果转换成JSON格式
        data = list(queryset.values("id","username","email"))

        return JsonResponse(data,safe=False)

　　通过浏览器访问，如下图所示：

 

 

四.Paginator和Page

1>.Paginator

C:\Users\yinzhengjie\softwares\GitHub\DevOps>python manage.py shell
Python 3.6.0 (v3.6.0:41df79263a11, Dec 23 2016, 08:06:12) [MSC v.1900 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>>
>>> from django.core.paginator import Paginator
>>>>>> from django.contrib.auth.models import User
>>>
>>> queryset = User.objects.all()
>>>
>>> paginator = Paginator(queryset,20)　　　　　　　　　　#实例化Paginator对象，下面的提示可以不用处理，说是咱们没有对数据进行排序
<string>:1: UnorderedObjectListWarning: Pagination may yield inconsistent results with an unordered object_list: <class 'django.contrib.auth.models.User'> QuerySet.
>>>

>>> paginator.count
1004
>>>

>>> paginator.num_pages
51
>>>

>>> paginator.page_range
range(1, 52)
>>>

 

2>.Page方法

>>> paginator.page(10)
<Page 10 of 51>
>>>

>>> page = paginator.page(10)
>>>
>>> page.object_list
<QuerySet [<User: yinzhengjie_176>, <User: yinzhengjie_177>, <User: yinzhengjie_178>, <User: yinzhengjie_179>, <User: yinzhengjie_180>, <User: yinzhengjie_181>, <User: yinzhengjie_182>, <User: yinzhengjie_183>, <User: yinzhengjie_184>, <User: yinzhengjie_185>, <User: yinzhengjie_186>, <User: yinzhengjie
_187>, <User: yinzhengjie_188>, <User: yinzhengjie_189>, <User: yinzhengjie_190>, <User: yinzhengjie_191>, <User: yinzhengjie_192>, <User: yinzhengjie_193>, <User: yinzhengjie_194>, <User: yinzhengjie_195>]>
>>>

>>> page.number
10
>>>

>>> page.paginator
<django.core.paginator.Paginator object at 0x0000000003BED2E8>
>>>

>>> page.has_next()
True
>>>

>>> page.has_previous()
True
>>>

>>> page.has_other_pages()
True
>>>

>>> page.next_page_number()
11
>>>

>>> page.previous_page_number()
9
>>>

>>> page.start_index()
181
>>>

>>> page.end_index()
200
>>>