django的模型層

時間 2019-11-24

標籤 django 模型欄目 Python 简体版

原文原文鏈接

django的模型層

一建立單表

1.建立模型

app01 models.py javascript

from django.db import models
# Create your models here.

class Book(models.Model):
     id=models.AutoField(primary_key=True)
     title=models.CharField(max_length=32,unique=True)
     pub_date=models.DateField()
     price=models.DecimalField(max_digits=8,decimal_places=2)
     publish=models.CharField(max_length=32)

2.配置數據庫

settings.pyphp

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME':'orm',           # 要鏈接的數據庫，鏈接前須要建立好
        'USER':'ysl',           # 鏈接數據庫的用戶名
        'PASSWORD':'123456',      # 鏈接數據庫的密碼
        'HOST':'10.0.0.51',       # 鏈接主機，默認本級
        'PORT':3306         #  端口 默認3306
    }
}

3. 配置mysql模塊

由於django默認你導入的驅動是MySQLdbcss

python3 mysql的驅動是 pymysql
因此在工orm __init__.py 寫入html

import pymysql
pymysql.install_as_MySQLdb()

4 打印 orm轉換過程當中的sql

settings.py 設置java

LOGGING = {

    'version': 1,
    'disable_existing_loggers': False,
    'handlers': {
        'console':{
            'level':'DEBUG',
            'class':'logging.StreamHandler',
        },

    },

    'loggers': {
        'django.db.backends': {
            'handlers': ['console'],
            'propagate': True,
            'level':'DEBUG',
        },
    }
}

5 命令行運行命令

python manage.py makemigrations
python manage.py migrate

二單表添加表記錄

from  app01.models import Book

def  index(request):

    # 添加表記錄

    #方式1
    # book_obj = Book(title="python",price=100,pub_date="2010-10-10",publish="人民出版社")
    # book_obj.save()


    #方式2
    # book_obj = Book.objects.create(title="php",price=100,pub_date="2011-10-10",publish="人民出版社")
    # print(book_obj.title)  #php
    # print(book_obj.price)   #100
    # print(book_obj.pub_date)    #2011-10-10


return    HttpResponse("ok")

三查詢表記錄

1 all() 方法

調用者Book.objects  返回值 queryset對象

    # 1）all()方法  調用者Book.objects  返回值 queryset對象
    book_list = Book.objects.all()
    print(book_list)
    #[<Book: Book object (1)>, <Book: Book object (2)>]   [obj1,obj2]

    for obj in  book_list:
        print(obj.title,obj.price)
        
    # python 100.00
    # php 100.00
    # go  200.00

2 first（）方法 last（）方法

 調用者 queryset 對象   返回值：model對象

 # 2) first  last 調用者 queryset 對象   返回值：model對象

    book_list = Book.objects.all().first()
    book_list = Book.objects.all()[0]

    print(book_list)

3 filter() 方法

調用者Book.objects 返回值queryset對象python

# 3)  filter() 調用者Book.objects    返回值queryset對象
book_list = Book.objects.filter(price=100)
print(book_list)
 #<QuerySet [<Book: python>, <Book: php>]>

book_obj = Book.objects.filter(price=100).first()
print(book_obj)

ret = Book.objects.filter(price=100,title='python')
print(ret)

4 get() 方法

有且只有一個查詢結果時纔有意義返回值:model對象mysql

# 4)  get  有且只有一個查詢結果時纔有意義  返回值:model對象
book_obj = Book.objects.get(title="go")
book_obj=Book.objects.get(price=100)
print(book_obj.price)

5 exclude() 方法

調用者Book.objects    返回值 queryset對象   排除go   其餘的都打印出來

ret = Book.objects.exclude(title="go")
print(ret)

6 order_by（）方法

order_by  排序   調用者: queryset對象   返回值:  queryset對象

ret = Book.objects.all().order_by("id")  #-id  desc       id asc
ret=Book.objects.all().order_by("price","id")
print(ret)

7 count()

調用者: queryset對象返回值: intjquery

ret = Book.objects.all().count()
print(ret)

8 exist() 是否爲空

ret = Book.objects.all().exists()
if ret:
    print("ok")

9 values() 方法

調用者: queryset對象  返回值:queryset對象

# ret = Book.objects.all()
# for i in ret:
#     print(i.title)

ret = Book.objects.all().values('title')
print(ret)
#<QuerySet [{'title': 'go'}, {'title': 'php'}, {'title': 'python'}]>
print(ret[0].get("title"))
#go

10 values_list() 方法

調用者: queryset對象返回值:queryset對象git

ret = Book.objects.all().values_list("price", "title")
print(ret)
# <QuerySet [(Decimal('100.00'), 'python'), (Decimal('100.00'), 'php'), (Decimal('200.00'), 'go')]>

11 distinct() 方法

調用者: queryset對象  返回值:queryset對象

ret = Book.objects.all().values("price").distinct()
print(ret)

#<QuerySet [{'price': Decimal('100.00')}, {'price': Decimal('200.00')}]>

四單表查詢之模糊查詢

Book.objects.filter(price__in=[100,200,300])
Book.objects.filter(price__gt=100)
Book.objects.filter(price__lt=100)
Book.objects.filter(price__range=[100,200])
Book.objects.filter(title__contains="python")
# 不區分p大小寫
Book.objects.filter(title__icontains="Python")
Book.objects.filter(title__startswith="py")
Book.objects.filter(pub_date__year=2012)

五刪除，修改記錄

1 刪除記錄

delete: 調用者: queryset對象 model對象sql

ret=Book.objects.filter(price=100).delete()
 print(ret)

Book.objects.filter(price=100).first().delete()

2 修改記錄

update : 調用者: queryset對象

ret=Book.objects.filter(title="php2").update(title="php")

六練習單表查詢圖書系統

　　實現功能：book單表的增刪改查

1 建立對應的mysql表

app01/modeles.py

from django.db import models
# Create your models here.

class Book(models.Model):
     id=models.AutoField(primary_key=True)
     title=models.CharField(max_length=32,unique=True)
     pub_date=models.DateField()
     price=models.DecimalField(max_digits=8,decimal_places=2)
     publish=models.CharField(max_length=32)

     def __str__(self):
          return self.title

2 設置mysql

ORM/ORM/setting.py

1）設置mysql

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME':'orm',       # 要鏈接的數據庫，鏈接前須要建立好
        'USER':'ysl',       # 鏈接數據庫的用戶名
        'PASSWORD':'123456',      # 鏈接數據庫的密碼
        'HOST':'10.0.0.51',       # 鏈接主機，默認本級
        'PORT':3306     #  端口 默認3306
    }
}

2）把app01註冊到項目中

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'app01',

]

3）配置靜態文件

# static 是靜態文件的別名
STATIC_URL = '/static/'


# 配置 靜態文件
STATICFILES_DIRS=[
    os.path.join(BASE_DIR,"static"),
]

4）打印orm轉換過程當中的sql

LOGGING = {
    'version': 1,
    'disable_existing_loggers': False,
    'handlers': {
        'console':{
            'level':'DEBUG',
            'class':'logging.StreamHandler',
        },
    },

    'loggers': {
        'django.db.backends': {
            'handlers': ['console'],
            'propagate': True,
            'level':'DEBUG',
        },
    }
}

5) 配置mysql模塊

由於django默認你導入的驅動是MySQLdb

python3 mysql的驅動是 pymysql
因此在工orm __init__.py 寫入

import pymysql
pymysql.install_as_MySQLdb()

6）命令行運行命令

python manage.py makemigrations
python manage.py migrate

3 配置url地址

ORM/ORM/urls.py

from django.contrib import admin
from django.urls import path,re_path

from  app01 import  views

urlpatterns = [
    path('admin/', admin.site.urls),
    path("books/",views.books),
    path("addbook/",views.addbook),
    re_path("books/(\d+)/delete",views.delete),
    re_path("books/(\d+)/change",views.change),
]

4 配置視圖

app01/views.py

def books(request):

    book_list = Book.objects.all()

    return  render(request,"books.html",locals())



def  addbook(request):

    if request.method=="POST":
        title = request.POST.get("title")
        price = request.POST.get("price")
        date = request.POST.get("date")
        publish = request.POST.get("publish")

        Book.objects.create(title=title,price=price,pub_date=date,publish=publish)

        return redirect("/books/")

    return render(request, "addbook.html")




def delete(request,id):
    Book.objects.filter(id=id).delete()

    return redirect("/books/")




def change(request,id):
    book_obj = Book.objects.filter(id=id).first()

    if request.method=="POST":
        title = request.POST.get("title")
        price = request.POST.get("price")
        date = request.POST.get("date")
        publish = request.POST.get("publish")
        Book.objects.filter(id=id).update(title=title,price=price,pub_date=date,publish=publish)

        return redirect("/books/")

    return   render(request, "change.html",{"book_obj":book_obj})

5. 配置Template

1) 設置 static

2) 配置對應的模版

base.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <!-- 標題模版-->
    {% block title %}
        <title>base</title>
    {% endblock %}

    <link rel="stylesheet" type="text/css" href="/static/bootstrap-3.3.7/css/bootstrap.css">
    <script type="text/javascript" src="/static/jquery-3.4.1.js"></script>

    <style>

        .header {
            width: 100%;
            height: 50px;
            background-color: #369;
            font-size: 40px;
            text-align: center;
            line-height: 50px;
        }
    </style>

</head>
<body>
<div class="header" >圖書管理系統</div>
<div class="container" style="margin-top: 100px;">
    <div class="row">
        <div class="col-lg-6 col-lg-offset-3">
            {% block  content %}
            
            {% endblock %}

        </div>
    </div>

</div>

</body>
</html>

base.html

books.html

{% extends "base.html" %}


{% block title %}
    <title>books</title>
{% endblock title %}

{% block content %}
    <a href="/addbook/" class="btn btn-primary btn-lg">添加書籍</a>

    <table class="table table-bordered table-hover" style="margin-top: 10px;">
        <tr>
            <th>書籍名稱</th>
            <th>價格</th>
            <th>出版日期</th>
            <th>出版社</th>
            <th>刪除操做</th>
            <th>編輯操做</th>
        </tr>
        {% for book in book_list %}
            <tr>
                <td>{{ book.title }}</td>
                <td>{{ book.price }}</td>
                <td>{{ book.pub_date|date:'Y-m-d' }}</td>
                <td>{{ book.publish }}</td>
                <td><a href="/books/{{ book.pk }}/delete" class="btn btn-danger">刪除</a></td>
                <td><a href="/books/{{ book.pk }}/change" class="btn btn-info">編輯</a></td>
            </tr>


        {% endfor content%}

    </table>
{% endblock %}

books.html

addbook.html

{% extends "base.html" %}


{% block title %}
<title>addbook</title>
{% endblock %}



{% block content %}
    <form action="" method="post">
        {% csrf_token %}
        <div>
            <label for="">數據名稱</label>
            <input type="text" class="form-control" name="title">
        </div>
        <div>
            <label for="">價格</label>
            <input type="text" class="form-control" name="price">
        </div>
        <div>
            <label for="">出版日期</label>
            <input type="date" class="form-control" name="date">
        </div>
        <div>
            <label for="">出版社</label>
            <input type="text" class="form-control" name="publish">
        </div>

    <input  type="submit" class="btn btn-success btn-lg pull-right" style="margin-top: 10px;">
    </form>
{% endblock %}

addbook.html

change.html

{% extends "base.html" %}


{% block title %}
<title>change</title>
{% endblock %}




{% block content %}
    <form action="" method="post">
        {% csrf_token %}
        <div>
            <label for="">數據名稱</label>
            <input type="text" class="form-control" name="title" value="{{ book_obj.title }}">
        </div>
        <div>
            <label for="">價格</label>
            <input type="text" class="form-control" name="price" value="{{ book_obj.price }}">
        </div>
        <div>
            <label for="">出版日期</label>
            <input type="date" class="form-control" name="date" value="{{ book_obj.pub_date|date:'Y-m-d' }}">
        </div>
        <div>
            <label for="">出版社</label>
            <input type="text" class="form-control" name="publish" value="{{ book_obj.publish }}">
        </div>

    <input  type="submit" class="btn btn-success btn-lg pull-right" style="margin-top: 10px;">
    </form>
{% endblock %}