批量插入数据
后端:
def fenye(request):
book_list=[]
for i in range(100):
book_list.append(models.Book(title='第%s本书'%i))
models.Book.objects.bulk_create(book_list)
book_qurery=models.Book.objects.all()
return render(request,'fenye.html',locals())
前端:
{% for book_list in book_qurery %}
<p>{{ book_list.title }}</p>
{% endfor %}
网页分页操作
class Pagination(object):
def __init__(self, current_page, all_count, per_page_num=10, 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)
使用自定义的分页,实现分页功能
后端:
from app01.utils.mypage import Pagination
def fenye1(request):
book_list = []
for i in range(100):
book_list.append(models.Book(title='第%s本书' % i))
models.Book.objects.bulk_create(book_list)
book_query=models.Book.objects.all()
current_page=request.GET.get('page',1)
all_count=book_query.count()
page_obj=Pagination(current_page=current_page,all_count=all_count)
page_query=book_query[page_obj.start:page_obj.end]
return render(request,'fenye1.html',locals())
前端:
{% for book_obj in page_query %}
<p>{{ book_obj.title }}</p>
{% endfor %}
{{ page_obj.page_html|safe }}
创建多对多表关系的三种方式
1、全自动
好处在于django orm会自动帮你创建第三张关系表,但是它只会帮你创建两个表的关系字段,不会再额外添加字段,虽然方便,但是第三张表的扩展性较差,无法随意的添加额外的字段
2、纯手动
好处在于第三张表可以任意的添加额外的字段,不足之处在于orm查询的时候,很多方法都不支持,查询的时候非常麻烦
3、半自动
手动建表,但是你会告诉orm第三张表是你自己建的,orm只需要给我提供方便的查询方法,第三种虽然可以使用orm查询方法,但不支持使用:add(),set(),remove(),clear()
class Book(models.Model):
authors=models.ManyToManyField(to='Author',through='Book_Author',through_fields('book','author'))
class Author(models.Model):
books=models.ManyToManyField(to='Book',through='Book_Author',though_fields=('author','book'))
class Book_Author(models.Model):
book=models.ForeignKey(to='Book')
author=models.ForeignKey(to='Author')
create_time=models.DateField(auto_now_add=True)
半自动,一定要加两个额外的参数
through='Book_Author',through_fields=('book','author')
后面字段的顺序
由第三张表通过哪个字段查询单表,就把哪个字段放前面
form校验组件
注册功能:
- 用户输入的用户名中不能包含“不好”,如果包含了就提示用户,输入的内容充满消极意义
- 用户输入的密码,不能小于三位,如果少于三位,提示用户密码太短了
校验数据通常是前后端都有校验.前端可有不校验,后端必须校验
如何取消前端帮我们做的校验 form表单中添加一个参数即可,</form action="" method="post" novalidate>
form组件能够自动帮你完成:
-
渲染页面
-
-
校验数据
-
展示错误信息
展示错误信息 用对象点errors.0 <form action="" method="post" novalidate> {% for foo in form_obj %} <p> {{ foo.label }}:{{ foo }} <span style="color: red">{{ foo.errors.0 }}</span> </p> {% endfor %} <input type="submit"> </form>
Form常用字段与插件
-
initial:初始值,input框里面的初始值 initial=‘初始值’
-
error_messages:重写错误信息 error_messages={"required":'不能为空 ',“invalid”:'格式错误'}
-
min_length/max_length: 最短长度/最大长度
-
label :显示文本内容
-
required=True 是否允许为空
-
widget=None html插件
-
help_text=' ' 初始值
-
validatores=[] 自定义验证规则
-
lacalize=False 是否支持本地化
-
disabled·=False 是否可编辑
-
label_suffix=None label内容后缀
-
strip=True 是否移除用户输入空白
-
decimal_places=None 小数位长度
-
input_formats=None 时间格式化
-
DateField(BaseTemporaField) 格式:2019-10-23
-
TimeField(BaseTemporalField) 格式:11:12
-
DateTimeField(BaseTemporalField) 格式:2015-09-11 11:12
-
regex :自定制正则表达式
-
allow_empty_file=False 是否允许空文件
-
required=True 是否必填
-
widget=None 插件,默认select插件
-
radioSelect:单radio值为字符串
-
class LoginForm(forms.Form): username = forms.CharField( min_length=8, label="用户名", initial="张三", error_messages={ "required": "不能为空", "invalid": "格式错误", "min_length": "用户名最短8位" } ) pwd = forms.CharField(min_length=6, label="密码") gender = forms.fields.ChoiceField( choices=((1, "男"), (2, "女"), (3, "保密")), label="性别", initial=3, widget=forms.widgets.RadioSelect() )
-
单选Select
-
class LoginForm(forms.Form): ... hobby = forms.ChoiceField( choices=((1, "篮球"), (2, "足球"), (3, "双色球"), ), label="爱好", initial=3, widget=forms.widgets.Select() )
-
多选Select
-
class LoginForm(forms.Form): ... hobby = forms.MultipleChoiceField( choices=((1, "篮球"), (2, "足球"), (3, "双色球"), ), label="爱好", initial=[1, 3], widget=forms.widgets.SelectMultiple() )
-
单选checkbox
-
class LoginForm(forms.Form): ... keep = forms.ChoiceField( label="是否记住密码", initial="checked", widget=forms.widgets.CheckboxInput() )
-
多选checkbox
-
class LoginForm(forms.Form): ... hobby = forms.MultipleChoiceField( choices=((1, "篮球"), (2, "足球"), (3, "双色球"),), label="爱好", initial=[1, 3], widget=forms.widgets.CheckboxSelectMultiple() )
choice字段注意事项
在使用选择标签时,需要注意choices的选项可以配置从数据库中获取,但是由于是静态字段获取的值无法实时更新,需要重写构造方法从而实现choice实时更新
方式一: from django.forms import Form from django.forms import widgets from django.forms import fields class MyForm(Form): user = fields.ChoiceField( # choices=((1, '上海'), (2, '北京'),), initial=2, widget=widgets.Select ) def __init__(self, *args, **kwargs): super(MyForm,self).__init__(*args, **kwargs) # self.fields['user'].choices = ((1, '上海'), (2, '北京'),) # 或 self.fields['user'].choices = models.Classes.objects.all().values_list('id','caption') 方式二: from django import forms from django.forms import fields from django.forms import models as form_model class FInfo(forms.Form): authors = form_model.ModelMultipleChoiceField(queryset=models.NNewType.objects.all()) # 多选 # authors = form_model.ModelChoiceField(queryset=models.NNewType.objects.all()) # 单选
-
RegexValidator验证器
-
from django.forms import Form from django.forms import widgets from django.forms import fields from django.core.validators import RegexValidator class MyForm(Form): user = fields.CharField( validators=[RegexValidator(r'^[0-9]+$', '请输入数字'), RegexValidator(r'^159[0-9]+$', '数字必须以159开头')], )
局部钩子
在form类中定义clean_字段名()方法,就能够实现对特定字段进行校验
class LoginForm(forms.Form): username = forms.CharField( min_length=8, label="用户名", initial="张三", error_messages={ "required": "不能为空", "invalid": "格式错误", "min_length": "用户名最短8位" }, widget=forms.widgets.TextInput(attrs={"class": "form-control"}) ) ... # 定义局部钩子,用来校验username字段 def clean_username(self): value = self.cleaned_data.get("username") if "666" in value: raise ValidationError("光喊666是不行的") else: return value
全局钩子
在form类中定义clean()方法,就能够实现对字段进行全局校验
class LoginForm(forms.Form): ... password = forms.CharField( min_length=6, label="密码", widget=forms.widgets.PasswordInput(attrs={'class': 'form-control'}, render_value=True) ) re_password = forms.CharField( min_length=6, label="确认密码", widget=forms.widgets.PasswordInput(attrs={'class': 'form-control'}, render_value=True) ) ... # 定义全局的钩子,用来校验密码和确认密码字段是否相同 def clean(self): password_value = self.cleaned_data.get('password') re_password_value = self.cleaned_data.get('re_password') if password_value == re_password_value: return self.cleaned_data else: self.add_error('re_password', '两次密码不一致') raise ValidationError('两次密码不一致')
如何改变input框的type属性值
如何改变input框的type属性值 widget= widgets.TextInput() widget=widgets.PasswordInput() 如何让forms组件渲染出来的input框有form-control类属性 widget= widgets.TextInput(attrs={'class':'form-control others'}) # 如果有多个类属性 空格隔开 widget=widgets.PasswordInput(attrs={'class':'form-control others'})
-