Diango之图书管理系统编辑

一.F与Q查询

          model.py文件:

from django.db import models

class Product(models.Model):
    name = models.CharField(max_length=32)  # 都是类实例化出来的对象
    price = models.DecimalField(max_digits=8,decimal_places=2)
    maichu = models.IntegerField()
    kucun = models.IntegerField()
    info = MyCharField(max_length=32,null=True)  # 改字段可以为空def __str__(self):
        return '商品对象的名字:%s'%self.name

        在数据库中添加记录后:

              

        在test.py中的普通查询:

import os
if __name__ == "__main__":
    os.environ.setdefault("DJANGO_SETTINGS_MODULE", "day59.settings")
    import django
    django.setup()
    from app01 import models
    # 查询卖出数大于50的商品
    res = models.Product.objects.filter(maichu__gt=50)
    print(res)

      查询卖出数大于库存数的商品要使用F查询:

  from django.db.models import F,Q
    # F查询
    res = models.Product.objects.filter(maichu__gt=F('kucun'))
    print(res)
    # <QuerySet [<Product: 商品对象的名字:高跟鞋>]>

    其他F查询示例:

    # 将所有的商品的价格提高100块
    models.Product.objects.update(price=F('price')+100)

    # 将所有商品的名字后面都加一个爆款
    from django.db.models.functions import Concat
    from django.db.models import Value
    models.Product.objects.update(name=Concat(F('name'),Value('爆款')))

      Q查询:

    res = models.Product.objects.filter(price=188.88,name='连衣裙爆款')
    print(res)
    from django.db.models import F, Q
    res = models.Product.objects.filter(Q(price=188.88),Q(name='连衣裙爆款'))  # and
    res = models.Product.objects.filter(Q(price=188.88)|Q(name='连衣裙爆款'))  # or
    res = models.Product.objects.filter(Q(price=188.88)|~Q(name='连衣裙爆款'))  # not
    # 混合使用  需要注意的是Q对象必须放在普通的过滤条件前面
    res = models.Product.objects.filter(~Q(name='连衣裙爆款'),price=188.88)  # Q取反再和price交集
    print(res)

    Q查询补充 (如果过滤的条件是字符串的查询方式):

   # from django.db.models import F, Q
    q = Q()
    q.connector = 'or'  # 通过这个参数可以将Q对象默认的and关系变成or
    q.children.append(('price',300.00))
    q.children.append(('name','高跟鞋爆款'))
    res = models.Product.objects.filter(q)  # Q对象查询默认也是and
    print(res)

 二.事务

# 事务的ACID
    """
    原子性
    一致性
    隔离性
    持久性
    """

    from django.db import transaction
    from django.db.models import F
    with transaction.atomic():
        # 在with代码块儿写你的事务操作
        models.Product.objects.filter(id=1).update(kucun=F('kucun')-1)
        models.Product.objects.filter(id=1).update(maichu=F('maichu')+1)

    # 写其他代码逻辑

三.自定义orm字段

from django.db import models

# Create your models here.
class MyCharField(models.Field):
    def __init__(self,max_length,*args,**kwargs):
        self.max_length = max_length
        super().__init__(max_length=max_length,*args,**kwargs)

    def db_type(self, connection):
        return 'char(%s)'%self.max_length

class Product(models.Model):
    name = models.CharField(max_length=32)  # 都是类实例化出来的对象
    price = models.DecimalField(max_digits=8,decimal_places=2)
    maichu = models.IntegerField()
    kucun = models.IntegerField()
    info = MyCharField(max_length=32,null=True)  # 改字段可以为空

 四.only与defer (拿到的是一个对象  两者是相反的):

首先给product对象添加一个name属性,如果查询的恰好就是name,只需走一次数据库,如果查的是其他属性,比如price,  product对象无此属性,需要走多次数据库

    # res = models.Product.objects.values('name')
    # print(res)
    # < QuerySet[{'name': '丝袜爆款'}, {'name': '连衣裙爆款'}, {'name': '高跟鞋爆款'}] >

查询name字段: 走1次数据库
    res = models.Product.objects.only('name')
    for i in res:
        print(i.name)

查询price字段: 走4次数据库
    res = models.Product.objects.only('name')
    for i in res:
        print(i.price)

defer与only访问数据库的方式正好相反:

查询name字段: 走4次数据库
    res = models.Product.objects.defer('name')
    for i in res:
        print(i.name)

查询price字段: 走1次数据库
    res = models.Product.objects.defer('name')
    for i in res:
        print(i.price)

 五.choices字段

models.py:

class Product(models.Model):
    name = models.CharField(max_length=32)  # 都是类实例化出来的对象
    price = models.DecimalField(max_digits=8,decimal_places=2)
    maichu = models.IntegerField()
    kucun = models.IntegerField()
    # info = MyCharField(max_length=32,null=True)  # 改字段可以为空

    choices = ((1,'男'),(2,'女'),(3,'其他'))
    gender = models.IntegerField(choices=choices,default=2)

test.py:

    res = models.Product.objects.filter(id=1).first()
    print(res.gender)                #  1
    print(res.get_gender_display())  # 获取编号对应的中文注释   男
    创建时传数字:
    models.Product.objects.create(...gender=1)

 六.图书管理系统

   models.py:

class Book(models.Model):
    title = models.CharField(max_length=32)
    price = models.DecimalField(max_digits=8, decimal_places=2)
    publish_time = models.DateField(auto_now_add=True)

    publish = models.ForeignKey(to='Publish')
    authors = models.ManyToManyField(to='Author')


    def __str__(self):
        return '书籍对象的名字:%s'%self.title


class Publish(models.Model):
    name = models.CharField(max_length=32)
    addr = models.CharField(max_length=32)
    email = models.EmailField()

    def __str__(self):
        return '出版社对象的名字:%s'%self.name


class Author(models.Model):
    name = models.CharField(max_length=32)
    age = models.IntegerField()
    authordetail = models.OneToOneField(to='AuthorDetail')

    def __str__(self):
        return '作者对象的名字:%s'%self.name


class AuthorDetail(models.Model):
    phone = models.BigIntegerField()
    addr = models.CharField(max_length=32)

    def __str__(self):
        return '作者详情对象的名字:%s'%self.phone

     1.创建主页:

       urls.py:

urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^$', views.home),
]

      views.py:

from django.shortcuts import render,redirect,HttpResponse,reverse
from app01 import models
# Create your views here.
def home(request):
    return render(request,'home.html')

    home.html:

主页效果:

   2.查询所有书籍:

     urls.py:

 url(r'^admin/', admin.site.urls),
 url(r'^$', views.home),
 url(r'^book_list/', views.show_book,name='book_list'),

    views.py:

def show_book(request):
    # 先查询所有的书籍
    book_list = models.Book.objects.all()
    return render(request,'book_list.html',locals())

    book_list.html (继承主页页面,并在block区域添加表格):

{% extends 'home.html' %}


{% block content %}
    <a href="{% url 'book_add' %}" class="btn btn-success">添加</a>

<table class="table table-striped table-bordered table-hover">
    <thead>
        <tr>
            <th>id</th>
            <th>title</th>
            <th>price</th>
            <th>publish_time</th>
            <th>publish</th>
            <th>authors</th>
            <th>actions</th>
        </tr>
    </thead>
    <tbody>
        {% for book in book_list %}
            <tr>
                <td>{{ book.pk }}</td>
                <td>{{ book.title }}</td>
                <td>{{ book.price }}</td>
                <td>{{ book.publish_time|date:'Y-m-d' }}</td>
                <td>{{  book.publish.name }}</td>
                <td>
                    {% for author_obj in book.authors.all %}
                        {% if forloop.last %}
                            {{ author_obj.name }}
                            {% else %}
                            {{ author_obj.name }},
                        {% endif %}
                    {% endfor %}
                </td>
                <td>
                    <a href=" " class="btn btn-primary btn-sm">编辑</a>
                    <a href=" " class="btn btn-danger btn-sm">删除</a>
                </td>
            </tr>
        {% endfor %}
    </tbody>
</table>
{% endblock %}

      点击图书列表会打开book_list页面 (因为在home.html里面通过a链接到了book_list路由):

<a href="{% url 'book_list' %}" class="list-group-item">图书列表</a>

    效果:

  3.添加书籍:

      点击添加按钮,则跳转到add_book页面,所以需要在book_list.html 的a链接连到add_book路由:

<a href="{% url 'book_add' %}" class="btn btn-success">添加</a>

      urls.py:

    url(r'^admin/', admin.site.urls),
    url(r'^$', views.home),
    url(r'^book_list/', views.show_book,name='book_list'),
    url(r'^add_book/', views.add_book,name='book_add'),

     views.py:

  

from django.shortcuts import render,HttpResponse,redirect,reverse
from app01 import models

def add_book(request):
    if request.method == 'POST':
        # print(request.POST)

        title = request.POST.get("title")
        price = request.POST.get("price")
        publish_date = request.POST.get("date")
        publish_id = request.POST.get("publish")
        authors = request.POST.getlist("authors")
        # 数据库新增数据
        book_obj = models.Book.objects.create(title=title,price=price,publish_time=publish_date,publish_id=publish_id)
        # 你可以尝试用**request.POST来新增数据(字典拆开的value是列表,不可行)

        # 去书籍与作者的第三表手动创建关系
        book_obj.authors.add(*authors)
        # 跳转到图书的展示页面
        return redirect(reverse('book_list'))
    # 将出版社和作者数据全部传递给添加页面
    publish_list = models.Publish.objects.all()
    author_list = models.Author.objects.all()
    # get请求返回一个添加页面
    return render(request,'add_book.html',locals())

         add_book.html:

{% extends 'home.html' %}


{% block content %}
<h1 class="text-center">添加书籍</h1>
    <form action="" method="post">
        <p>title:<input type="text" class="form-control" name="title"></p>
        <p>price:<input type="text" class="form-control" name="price"></p>
        <p>publish_date:<input type="date" class="form-control" name="date"></p>
        <p>publish:
            <select name="publish" id="" class="form-control">
                {% for publish in publish_list %}
                    <option value="{{ publish.pk }}">{{ publish.name }}</option>
                {% endfor %}
            </select>
        </p>
        <p>authors:
            <select name="authors" id="" class="form-control" multiple>
                {% for author in author_list %}
                    <option value="{{ author.pk }}">{{ author.name }}</option>
                {% endfor %}
            </select>
        </p>
        <input type="submit" class="btn btn-warning pull-right">
    </form>
{% endblock %}

</body>
</html>

   4.删除书籍:

        点击删除按钮,则跳转到delete_book页面,所以需要在book_list.html 的a链接连到delete_book路由:

<a href="{% url 'book_delete' book.pk %}" class="btn btn-danger btn-sm">删除</a>

         urls.py:

    url(r'^admin/', admin.site.urls),
    url(r'^$', views.home),
    url(r'^book_list/', views.show_book,name='book_list'),
    url(r'^add_book/', views.add_book,name='book_add'),
    url(r'^delete_book/(d+)/', views.delete_book,name='book_delete'),

      views.py:

def delete_book(request,delete_id):
    # 获取用户想要删除的数据的id???
    # print(delete_id)
    models.Book.objects.filter(pk=delete_id).delete()
    return redirect(reverse('book_list'))

    5.编辑书籍:

        点击编辑按钮,则跳转到edit_book页面,所以需要在book_list.html 的a链接连到edit_book路由:

<a href=" {% url 'book_edit' book.pk %}" class="btn btn-primary btn-sm">编辑</a>

       urls.py:

urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^$', views.home),
    url(r'^book_list/', views.show_book,name='book_list'),
    url(r'^add_book/', views.add_book,name='book_add'),
    url(r'^delete_book/(d+)/', views.delete_book,name='book_delete'),
    url(r'^edit_book/(d+)/', views.edit_book,name='book_edit'),
]

      views.py:

def edit_book(request,edit_id):
    # 返回一个编辑页面，但是你这个编辑页面需要将原来数据的信息展示出来
    edit_obj = models.Book.objects.filter(pk=edit_id).first()
    if request.method == 'POST':
        # print(request.POST)
        title = request.POST.get("title")
        price = request.POST.get("price")
        publish_date = request.POST.get("date")
        publish_id = request.POST.get("publish")
        authors = request.POST.getlist("authors")
        models.Book.objects.filter(pk=edit_id).update(title=title,price=price,publish_time=publish_date,publish_id=publish_id)
        edit_obj.authors.set(authors)
        return redirect(reverse('book_list'))

    publish_list = models.Publish.objects.all()
    author_list = models.Author.objects.all()
    return render(request,'edit.html',locals())

   edit.html:

{% extends 'home.html' %}


{% block content %}
    <h1 class="text-center">编辑书籍</h1>
    <form action="" method="post">
        <p>title:<input type="text" class="form-control" name="title" value="{{ edit_obj.title }}"></p>
        <p>price:<input type="text" class="form-control" name="price" value="{{ edit_obj.price }}"></p>
        <p>publish_date:<input type="date" class="form-control" name="date"
                               value="{{ edit_obj.publish_time|date:'Y-m-d' }}"></p>
        <p>publish:
            <select name="publish" id="" class="form-control">
                {% for publish in publish_list %}
                    {% if edit_obj.publish == publish %}
                        <option value="{{ publish.pk }}" selected>{{ publish.name }}</option>
                    {% else %}
                        <option value="{{ publish.pk }}">{{ publish.name }}</option>
                    {% endif %}

                {% endfor %}
            </select>
        </p>
        <p>authors:
            <select name="authors" id="" class="form-control" multiple>
                {% for author in author_list %}
                    {% if author in edit_obj.authors.all %}
                        <option value="{{ author.pk }}" selected>{{ author.name }}</option>
                    {% else %}
                        <option value="{{ author.pk }}">{{ author.name }}</option>
                    {% endif %}

                {% endfor %}
            </select>
        </p>
        <input type="submit" class="btn btn-warning pull-right">
    </form>
{% endblock %}