一、ajax结合sweetalert实现删除按钮的动态效果
- 下载sweetalert插件,导入dist文件夹中css和js文件
- 挑选弹出框样式,https://lipis.github.io/bootstrap-sweetalert/
- 通过自定义标签属性传输数据
- 通过标签的查找删除标签,达到删除的作用
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.min.js"></script>
{% load static %}
<link rel="stylesheet" href= {% static 'bootstrap-3.3.7-dist/css/bootstrap.min.css' %}>
<link rel="stylesheet" href= {% static 'dist/sweetalert.css' %}>
<script src={% static 'dist/sweetalert.min.js' %}></script>
<script src={% static 'bootstrap-3.3.7-dist/js/bootstrap.min.js' %}></script>
</head>
<body>
<div class="container-fluid">
<div class="row">
<div class="col-md-8 col-md-offset-2">
<table class="table-striped table table-bordered table-hover">
<thead>
<tr>
<th>序号</th>
<th>姓名</th>
<th>年龄</th>
<th>性别</th>
<th>操作</th>
</tr>
</thead>
<tbody>
{% for user in user_queryset %}
<tr>
<td>{{ forloop.counter }}</td>
<td>{{ user.username }}</td>
<td>{{ user.age }}</td>
<td>{{ user.get_gender_display }}</td>
<td>
<a href="" class="btn btn-success btn-sm">编辑</a>
<!--通过自定义标签属性传输user_id-->
<a href="#" class="cancel btn btn-danger btn-sm" userId= {{ user.pk }}>删除</a>
</td>
</tr>
{% endfor %}
</tbody>
</table>
</div>
</div>
</div>
<script>
$('.cancel').click(function () {
var $btn = $(this);
console.log($(this))
swal({
title: "Are you sure?",
text: "You will not be able to recover this imaginary file!",
type: "warning",
showCancelButton: true,
confirmButtonColor: "#DD6B55",
confirmButtonText: "Yes, delete it!",
cancelButtonText: "No, cancel plx!",
closeOnConfirm: false,
closeOnCancel: false
},
function (isConfirm) {
if (isConfirm) {
console.log($(this))
$.ajax({
url: '',
type: 'post',
// 通过标签自定义属性传输数据
data: {'user_id': $btn.attr('userId')},
success: function (data) {
if (data.code === 1000) {
swal("Deleted!", data.msg, "success");
// 通过标签的查找删除标签
$(this).parent().parent().remove()
} else {
swal("Cancelled", "Your imaginary file is safe :)", "warning");
}
}
})
} else {
swal("Cancelled", "Your imaginary file is safe :)", "error");
}
});
})
</script>
</body>
</html>
# views.py
from django.shortcuts import render
from django.http import JsonResponse
from app01 import models
# Create your views here.
def home(request):
if request.is_ajax():
user_id = request.POST.get('user_id')
models.User.objects.filter(pk=user_id).delete()
return JsonResponse({'code':1000,'msg':'删除成功'})
user_queryset = models.User.objects.all()
return render(request,'home.html',locals())
二、bulk_create批量插入数据
- bulk_create用于批量插入数据,解决大量插入数据耗时长的问题
- 先用列表生成数据,再通过bulk_create批量插入数据
def index(request):
book_list = []
for i in range(10000):
book_list.append(models.Book(title=f'第{i}本书'))
# 批量插入数据
models.Book.objects.bulk_create(book_list)
book_queryset = models.Book.objects.all()
return render(request,'index.html',locals())
三、自定义分页器
(一)手动推导
def index(request):
book_queryset = models.Book.objects.all()
all_page_count = book_queryset.count() # 数据总个数
per_page_count = 10 # 每页要展示的数据数目
page_num,mod = divmod(all_page_count,per_page_count)
if mod:
page_num +=1 # 总页数
current_page = request.GET.get('page',1) # 默认第一页
current_page = int(current_page)
xxx = current_page
# 前六页和后六页
if current_page < 6:
xxx = 6
elif current_page < page_num and current_page > page_num-6:
xxx = page_num-6
html = ''
for i in range(xxx-5,xxx+6):
if i==current_page:
html += f'<li class="active"><a href="?page={i}">{i} <span class="sr-only">(current)</span></a></li>'
else:
html+= f'<li class=""><a href="?page={i}">{i} <span class="sr-only">(current)</span></a></li>'
start_page = (current_page-1) * per_page_count
end_page = current_page*per_page_count
book_queryset = book_queryset[start_page:end_page]
return render(request,'index.html',locals())
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.min.js"></script>
{% load static %}
<link rel="stylesheet" href= {% static 'bootstrap-3.3.7-dist/css/bootstrap.min.css' %}>
<link rel="stylesheet" href= {% static 'dist/sweetalert.css' %}>
<script src={% static 'dist/sweetalert.min.js' %}></script>
<script src={% static 'bootstrap-3.3.7-dist/js/bootstrap.min.js' %}></script>
</head>
<body>
<div class="container-fluid">
<div class="row">
<div class="col-md-8">
{% for book_obj in book_queryset %}
<p>{{ book_obj }}</p>
{% endfor %}
<nav aria-label="Page navigation">
<ul class="pagination">
<li>
<a href="#" aria-label="Previous">
<span aria-hidden="true">«</span>
</a>
</li>
{{ html|safe }}
<li>
<a href="#" aria-label="Next">
<span aria-hidden="true">»</span>
</a>
</li>
</ul>
</nav>
</div>
</div>
</div>
</body>
</html>
(二)自定义分页器
(1)模板
class Pagination(object):
def __init__(self,current_page,all_count,per_page_num=2,pager_count=11):
"""
封装分页相关数据
:param current_page: 当前页
:param all_count: 数据库中的数据总条数
:param per_page_num: 每页显示的数据条数
:param pager_count: 最多显示的页码个数
用法:
queryset = model.objects.all()
page_obj = Pagination(current_page,all_count)
page_data = queryset[page_obj.start:page_obj.end]
获取数据用page_data而不再使用原始的queryset
获取前端分页样式用page_obj.page_html
"""
try:
current_page = int(current_page)
except Exception as e:
current_page = 1
if current_page <1:
current_page = 1
self.current_page = current_page
self.all_count = all_count
self.per_page_num = per_page_num
# 总页码
all_pager, tmp = divmod(all_count, per_page_num)
if tmp:
all_pager += 1
self.all_pager = all_pager
self.pager_count = pager_count
self.pager_count_half = int((pager_count - 1) / 2)
@property
def start(self):
return (self.current_page - 1) * self.per_page_num
@property
def end(self):
return self.current_page * self.per_page_num
def page_html(self):
# 如果总页码 < 11个:
if self.all_pager <= self.pager_count:
pager_start = 1
pager_end = self.all_pager + 1
# 总页码 > 11
else:
# 当前页如果<=页面上最多显示11/2个页码
if self.current_page <= self.pager_count_half:
pager_start = 1
pager_end = self.pager_count + 1
# 当前页大于5
else:
# 页码翻到最后
if (self.current_page + self.pager_count_half) > self.all_pager:
pager_end = self.all_pager + 1
pager_start = self.all_pager - self.pager_count + 1
else:
pager_start = self.current_page - self.pager_count_half
pager_end = self.current_page + self.pager_count_half + 1
page_html_list = []
# 添加前面的nav和ul标签
page_html_list.append('''
<nav aria-label='Page navigation>'
<ul class='pagination'>
''')
first_page = '<li><a href="?page=%s">首页</a></li>' % (1)
page_html_list.append(first_page)
if self.current_page <= 1:
prev_page = '<li class="disabled"><a href="#">上一页</a></li>'
else:
prev_page = '<li><a href="?page=%s">上一页</a></li>' % (self.current_page - 1,)
page_html_list.append(prev_page)
for i in range(pager_start, pager_end):
if i == self.current_page:
temp = '<li class="active"><a href="?page=%s">%s</a></li>' % (i, i,)
else:
temp = '<li><a href="?page=%s">%s</a></li>' % (i, i,)
page_html_list.append(temp)
if self.current_page >= self.all_pager:
next_page = '<li class="disabled"><a href="#">下一页</a></li>'
else:
next_page = '<li><a href="?page=%s">下一页</a></li>' % (self.current_page + 1,)
page_html_list.append(next_page)
last_page = '<li><a href="?page=%s">尾页</a></li>' % (self.all_pager,)
page_html_list.append(last_page)
# 尾部添加标签
page_html_list.append('''
</nav>
</ul>
''')
return ''.join(page_html_list)
(2)用法
- 应用中创建utils文件夹
- 文件夹中创建mypage.py文件
- 视图函数中导入该文件
- 当前页:current_page
- 数据总个数:all_count
- 实例化对象:page_obj
- 切片
# views.py
from app01.utils.mypage import Pagination
def index(request):
current_page = request.GET.get('page',1)
all_count = book_queryset.count()
page_obj = Pagination(current_page=current_page,all_count=all_count,per_page_num=10,pager_count=5)
page_queryset = book_queryset[page_obj.start:page_obj.end]
return render(request,'index.html',locals())
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.min.js"></script>
{% load static %}
<link rel="stylesheet" href="{% static 'bootstrap-3.3.7-dist/css/bootstrap.min.css' %}">
<link rel="stylesheet" href="{% static 'dist/sweetalert.css' %}">
<script src="{% static 'bootstrap-3.3.7-dist/js/bootstrap.min.js' %}"></script>
<script src="{% static 'dist/sweetalert.min.js' %}"></script>
</head>
<body>
<div class="container-fluid">
<div class="row">
<div class="col-md-8 col-md-offset-2">
{% for book in page_queryset %}
<p>{{ book }}</p>
{% endfor %}
{{ page_obj.page_html|safe }}
</div>
</div>
</div>
</body>
</html>
orm查询优化
only和defer
- only
- only返回的是queryset对象,本质就是列表套数据对象
- 该对象内只含有only括号内指定的属性,但是其他属性也可以获取,会自动从数据库重新获取
- defer
- defer返回的是queryset对象,本质就是列表套数据对象
- 该对象内只含有除了defer括号内所指定的其他属性,指定属性也可获取,也会自动从数据库重新获取
- only
select_related和prefetch_related
- select_related
- 括号内只能放外键字段,并且外键字段的类型只能是一对多或者多对多
- 内部是联表操作,返回的是一个queryset列表套数据对象
- 获取外键表数据时,不会再访问数据库
- prefetch_related
- 内部是子查询,括号内外键字段无限制
- 内部是联表操作,返回的是一个queryset列表套数据对象
- 获取外键表数据时,不会再访问数据库
第一个方法联表操作比较耗时、第二个方法访问数据库比较耗时
- select_related
choices参数
- 提前定义好对应关系
- 再通过字段的choices参数指定关系
get_字段名_display
:获取对应关系
MTC和MVC模型
MTC
- Models
- Templates
- Views
MVC
- Models
- Views
- Controller
django自称是MTV,本质上还是MVC
AJAX
- 异步提交
- 局部刷新
AJAX基本语法结构
- url:后端的地址,特性和action一样
- type:请求方式
- data:传输数据
success:基于ajax,后端返回的结果(HttpResponse)会被回调函数捕获,不会影响整个页面
// 基于Jquery封装好的ajax,确保jQuery导入 $.ajax({ url:'', type:'post', data:{'username':'wick'} success:function(data){ } })
- 前后端数据传输编码格式
- urlencoded
- 数据格式:usernamewick&password=123
- django针对符合urlencoded编码格式的数据,会自动解析并封装到request.POST中
- formdata
- form表单发送文件必须要指定的编码格式
- 可以发文件也可以发普通键值对
- django后端会自动识别,将内部符合urlencoded编码格式的数据,会自动东借西并封装到request.FILES中
- application/json
- 用来发送json格式数据
- 目前只有ajax能发送jaon格式数据
- urlencoded
- ajax发送json格式数据
- contenType:'application/json'
- JSON.stringify({'username':'wick'$'password':123})
- django针对json格式数据不会自动处理,会封装在requerst.body内,需要手动反序列化
- ajax发送文件数据
- 先生成一个内置对象:
var MyFormData=new FormData()
- 通过append向对象内添加数据(可以是普通键值对,也可以是文件)
- 普通键值对:MyFormData.append('name','wick')
- 文件数据:MyFormData.append('file',$('input')[0].file[0])
- 额外指定两个参数
- contentType:false
- processData:false
- 先生成一个内置对象: