django进阶

Posted 2020-09-05 人生苦短，我用python

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django ORM操作

models.py

from django.db import models

# Create your models here.
class Book(models.Model):
    name = models.CharField(max_length=128)
    price = models.PositiveSmallIntegerField(null=True)#正数,null=True不是必填
    authors = models.ManyToManyField(‘Author‘)
    publisher = models.ForeignKey(‘Publisher‘)
    pub_date = models.DateField()
    # memo = models.CharField(null=True,max_length=64)数据库新增字段的时候，需要加上null=True
    #为了在查询时显示对象的名字
    def __str__(self):
        return self.name

class Author(models.Model):
    name = models.CharField(max_length=32)
    email = models.EmailField(unique=True)

    def __str__(self):
        return self.name

class Publisher(models.Model):
    name = models.CharField(max_length=128,unique=True)
    website = models.URLField(unique=True)

    def __str__(self):
        return "%s %s"%(self.name,self.website)

terminal下进行数据库的增删改查

python3 manage.py shell
from app01 import models

book表增加数据，关联author和publisher表，所以先创建author和publisher,创建时不能直接指定author

models.Author.objects.create(name=‘alex‘,email=‘[email protected]‘)
models.Publisher.objects.create(name=‘tsinghua‘,website=‘http://tsinghua.com)

b2 = models.Book.objects.create(name=‘linux‘,price=55,publisher_id=2,pub_date=‘2016-01-01‘)
b2.authors.add(1,2)
b2.authors.all()#查询这本书的作者，创建完之后是保存在app01_book_authors表中
b2.authors.remove()
b2.publiser.name#查看外键关键的表的属性

查

返回列表　　models.Book.objects.fliter()

返回单个对象或错误，如果get到多条会报错　　models.Book.objects.get()

models.Book.objects.get(pub_date__gt = ‘2017-01-01‘)

查询没有就创建

　　models.Book.objects.get_or_create(name=‘java‘,pub_date=‘2019-01-01‘,publisher_id=1)

　　(<Book: java>, True)

包含(contains,incontains忽略大小写)

　　models.Book.objects.filter(name__contains=‘go‘)

查name和price

　　models.Book.objects.values(‘name‘,‘price‘)

查价格不等于50的book

　　models.Book.objects.exclude(price=50)

aggregate　　聚合

　　书的平均价格

　　from django.db.models import Avg,Sum,Max,Min,Count

　　models.Book.objects.all().aggregate(Avg(‘price‘))

　　每个出版社出的书和书的平均价格

　　from django.db.models import Count

　　models.Book.objects.values(‘publisher__name‘).annotate(Count(‘id‘))

　　models.Book.objects.values(‘publisher__name‘).annotate(Avg(‘price‘))

　　2016或2017出版的书

　　q = Q(pub_date__year=‘2016‘)|Q(pub_date__year=‘2017‘)
　　models.Book.objects.filter(q)
　　<QuerySet [<Book: python>, <Book: linux>]>

　　自修改

　　　　from django.db.models import F

　　　　models.Book.objects.update(price=F(‘price‘)+10)

　　本表两字段比较

　　　　from datetime import timedelta

　　　　models.Book.objects.filter(pub_date__lt=F(‘pub_date‘)+timedelta(days=3))

　　字段迁移

　　　　from django.db.models import F

　　　　models.Book.objects.update(memo=F(‘name‘))

通过出版社查询每个出版社出了多少书

　　p1 = models.Publisher.objects.all()[1]

　　p1.book_set.all()

FORM表单

1、app01下创建文件forms.py

from django import forms
from app01 import models
FAVORITE_COLORS_CHOICES=(
    (‘blue‘,‘BLUE‘),
    (‘green‘,‘Green‘),
    (‘black‘,‘Black‘),
)
BIRTH_YEAR_CHOICES = (‘1980‘,‘1981‘,‘1982‘)
seat_CHOICE = ((‘1‘,‘First‘,),(‘2‘,‘Second‘,))

import re
def mobile_validate(value):
    mobile_re = re.compile(r‘^(13[0-9]|15[012356789]|17[678]|18[0-9]|14[57])[0-9]{8}$‘)
    if not mobile_re.match(str(value)):
        raise forms.ValidationError(‘手机号码格式错误‘)


class MailSendForm(forms.Form):
    sender = forms.EmailField()
    receiver = forms.EmailField()
    subject = forms.CharField(max_length=12)
    content = forms.CharField(widget=forms.Textarea(attrs={‘cols‘:100,
                                                           ‘class‘:‘font-color‘,
                                                           ‘style‘:‘background-color:lightgreen‘}))
    birth_year = forms.DateField(widget=forms.SelectDateWidget(years=BIRTH_YEAR_CHOICES))
    mobile = forms.IntegerField(validators=[mobile_validate, ],
                                error_messages={‘required‘: ‘手机不能为空‘},
                                widget=forms.TextInput(attrs={‘class‘: ‘form-control‘,
                                                              ‘placeholder‘: ‘手机号码‘}))

    choice_field = forms.ChoiceField(widget=forms.Radioselect,choices=seat_CHOICE)
    favorite_colors = forms.MultipleChoiceField(
        widget=forms.CheckboxSelectMultiple,
        choices=FAVORITE_COLORS_CHOICES,
    )
    def clean_sender(self):#对哪个字段做认证，就clean_xx
        print(‘validate sender‘,self.cleaned_data)
        if self.cleaned_data.get(‘sender‘) != ‘[email protected]‘:
            self.add_error(‘sender‘,‘only‘)
        return self.cleaned_data.get(‘sender‘)#不返回的话cleaned_data里面‘sender‘为None

    def clean(self):#所有的clean_field都验证完成后，才会执行
        print(‘clean data‘,self.cleaned_data)
        sender = self.cleaned_data.get(‘sender‘)
        receiver = self.cleaned_data.get(‘receiver‘)
        if sender == receiver:
            raise forms.ValidationError(‘发送者和接受者不能相同‘)

class BookForm(forms.ModelForm):
    class Meta:
        model = models.Book
        fields = "__all__"
        exclude = [‘memo‘,]

2、views.py

from django.shortcuts import render
from app01.forms import MailSendForm
from app01.forms import BookForm
from django.views import View
# Create your views here.
def mail(request):
    if request.method == ‘POST‘:
        form = MailSendForm(request.POST)
        if form.has_changed():
            print(‘form has changed‘)
        if form.is_valid():#验证表单数据是否合法
            print(‘fuck‘,form.cleaned_data)
        else:
            print(‘error‘,form.errors)

    else:
        form = MailSendForm(initial={‘sender‘:‘[email protected]‘})

    return render(request,‘mail_send.html‘,{‘form‘:form})

def book_mgr(request):
    if request.method == ‘POST‘:
        form = BookForm(data=request.POST)
        if form.is_valid():
            form.save()
            form = BookForm()
    else:
        form = BookForm()
    return render(request,‘book.html‘,{‘form‘:form})
class BookMgr(View):
    form_class = BookForm
    template_name = ‘book.html‘

    def get(self,request):
        print(‘get‘,request.GET)
        form = self.form_class()
        return render(request,self.template_name,{‘form‘:form})

    def post(self,request):
        form = self.form_class(data=request.POST)
        if form.is_valid():
            form.save()
            form = self.form_class()
        return render(request,self.template_name,{‘form‘:form})

3、mail_send.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <div>
        <form method="post">
            {% for item in form %}
                <div>
                    {{ item.label }} {{ item }}
                    {% if item.errors %}
                        <span style="color: red">
                            {{ item.errors }}
                        </span>

                    {% endif %}
                </div>

            {% endfor %}
            <input type="submit" value="send"/>
        </form>
    </div>
</body>
</html>

modelform

form.py

class BookForm(forms.ModelForm):
    class Meta:
        model = models.Book
        fields = "__all__"
        exclude = [‘memo‘,]

view.py

def book_mgr(request):
    if request.method == ‘POST‘:
        form = BookForm(data=request.POST)
        if form.is_valid():
            form.save()
            form = BookForm()
    else:
        form = BookForm()
    return render(request,‘book.html‘,{‘form‘:form})

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django ORM操作

查

aggregate 聚合

FORM表单

aggregate　　聚合