因爲前面在centos實驗的過程當中,pymql一直有屬性錯誤,很難排查出問題,從新作了一個ubuntu的桌面系統同時使用pycharm開發工具做爲學習開發工具,具體緣由是由於在項目命名出現問題,和本身帶的模塊衝突,致使不能成功html
對象關係映射(Object Relational Mapping,簡稱ORM)。node
簡單的說,ORM是經過使用描述對象和數據庫之間映射的元數據,將程序中的對象自動持久化到關係數據庫中。ORM在業務邏輯層和數據庫層之間充當了橋樑的做用。python
經過一張圖來介紹一下數據庫與python代碼之間的一個關係:mysql
ORM的優勢git
ORM的缺點正則表達式
若是想打印orm轉換過程當中的sql,須要在settings中進行以下配置: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', }, } } settings配置
django使用MySQL的流程:數據庫
注意:ORM沒法操做到數據庫級別,只能操做到數據表。django
安裝mysqlubuntu
apt-get install mysql-server mysql-common mysql-client
root@darren-virtual-machine:~# systemctl status mysql
mysql.service - MySQL Community Server Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: enabled) Active: active (running) since Sun 2020-04-05 11:46:45 CST; 58s ago Main PID: 16219 (mysqld) Tasks: 27 (limit: 11869) CGroup: /system.slice/mysql.service └─16219 /usr/sbin/mysqld --daemonize --pid-file=/run/mysqld/mysqld.pid 4月 05 11:46:44 darren-virtual-machine systemd[1]: Starting MySQL Community Server... 4月 05 11:46:45 darren-virtual-machine systemd[1]: Started MySQL Community Server.
root@darren-virtual-machine:~# mysql -V
mysql Ver 14.14 Distrib 5.7.29, for Linux (x86_64) using EditLine wrapper
root@darren-virtual-machine:~# cat /etc/mysql/debian.cnf
# Automatically generated for Debian scripts. DO NOT TOUCH! [client] host = localhost user = debian-sys-maint password = gpitUmpta6ImT8hh socket = /var/run/mysqld/mysqld.sock [mysql_upgrade] host = localhost user = debian-sys-maint password = gpitUmpta6ImT8hh socket = /var/run/mysqld/mysqld.sock
可使用上面的用戶名和密碼,也能夠直接登陸
登陸mysql
mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | +--------------------+ 4 rows in set (0.00 sec) mysql> use mysql; Reading table information for completion of table and column names You can turn off this feature to get a quicker startup with -A Database changed mysql> update user set authentication_string=PASSWORD("123456") where user='root'; Query OK, 1 row affected, 1 warning (0.00 sec) Rows matched: 1 Changed: 1 Warnings: 1 mysql> update user set plugin="mysql_native_password"; Query OK, 1 row affected (0.00 sec) Rows matched: 4 Changed: 1 Warnings: 0 mysql> flush privileges; Query OK, 0 rows affected (0.00 sec) mysql> quit
root@darren-virtual-machine:~# mysql -uroot -p123456
mysql> create database django default charset=utf8; Query OK, 1 row affected (0.00 sec) mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | django | | mysql | | performance_schema | | sys | +--------------------+ 5 rows in set (0.00 sec)
root@darren-virtual-machine:~# cd /root/PycharmProjects/
root@darren-virtual-machine:~/PycharmProjects# django-admin startproject mystie
root@darren-virtual-machine:~/PycharmProjects# cd mysite/
root@darren-virtual-machine:~/PycharmProjects/mysite# tree ./*
./manage.py [error opening dir] ./mysite ├── asgi.py ├── __init__.py ├── settings.py ├── urls.py └── wsgi.py
root@darren-virtual-machine:~/PycharmProjects/mysite# python3 manage.py startapp app01
root@darren-virtual-machine:~/PycharmProjects/mysite# vim mysite/settings.py
INSTALLED_APPS = [ 'django.contrib.admin', 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.messages', 'django.contrib.staticfiles', 'app01.apps.App01Config', ]
DATABASES = { 'default': { 'ENGINE': 'django.db.backends.mysql', 'NAME': 'django', 'HOST': '127.0.0.1', 'PORT': 3306, 'USER': "root", 'PASSWORD': "123456", } }
root@darren-virtual-machine:~/PycharmProjects/mysite# pip3 install pymysql
Collecting pymysql Downloading PyMySQL-0.9.3-py2.py3-none-any.whl (47 kB) |████████████████████████████████| 47 kB 175 kB/s Installing collected packages: pymysql Successfully installed pymysql-0.9.3
root@darren-virtual-machine:~/PycharmProjects/mysite# vim mysite/__init__.py
# 在與settings.py同級目錄下的__init__.py中
import pymysql
pymysql.install_as_MySQLdb()
[root@node10 pymysql]# cat app01/models.py
from django.db import models # Create your models here. class Book(models.Model): title = models.CharField(max_length=32) author = models.CharField(max_length=32) publisher = models.CharField(max_length=32) price = models.DecimalField(max_digits=5, decimal_places=2) pub_date = models.DateField()
擴展:更多字段和參數
每一個字段有一些特有的參數,例如,CharField須要max_length參數來指定VARCHAR
數據庫字段的大小。還有一些適用於全部字段的通用參數。 這些參數在文檔中有詳細定義,這裏咱們只簡單介紹一些最經常使用的:
更多字段:
<1> CharField 字符串字段, 用於較短的字符串. CharField 要求必須有一個參數 maxlength, 用於從數據庫層和Django校驗層限制該字段所容許的最大字符數. <2> IntegerField #用於保存一個整數. <3> FloatField 一個浮點數. 必須 提供兩個參數: 參數 描述 max_digits 總位數(不包括小數點和符號) decimal_places 小數位數 舉例來講, 要保存最大值爲 999 (小數點後保存2位),你要這樣定義字段: models.FloatField(..., max_digits=5, decimal_places=2) 要保存最大值一百萬(小數點後保存10位)的話,你要這樣定義: models.FloatField(..., max_digits=19, decimal_places=10) admin 用一個文本框(<input type="text">)表示該字段保存的數據. <4> AutoField 一個 IntegerField, 添加記錄時它會自動增加. 你一般不須要直接使用這個字段; 自定義一個主鍵:my_id=models.AutoField(primary_key=True) 若是你不指定主鍵的話,系統會自動添加一個主鍵字段到你的 model. <5> BooleanField A true/false field. admin 用 checkbox 來表示此類字段. <6> TextField 一個容量很大的文本字段. admin 用一個 <textarea> (文本區域)表示該字段數據.(一個多行編輯框). <7> EmailField 一個帶有檢查Email合法性的 CharField,不接受 maxlength 參數. <8> DateField 一個日期字段. 共有下列額外的可選參數: Argument 描述 auto_now 當對象被保存時,自動將該字段的值設置爲當前時間.一般用於表示 "last-modified" 時間戳. auto_now_add 當對象首次被建立時,自動將該字段的值設置爲當前時間.一般用於表示對象建立時間. <1> CharField 字符串字段, 用於較短的字符串. CharField 要求必須有一個參數 maxlength, 用於從數據庫層和Django校驗層限制該字段所容許的最大字符數. <2> IntegerField #用於保存一個整數. <3> FloatField 一個浮點數. 必須 提供兩個參數: 參數 描述 max_digits 總位數(不包括小數點和符號) decimal_places 小數位數 舉例來講, 要保存最大值爲 999 (小數點後保存2位),你要這樣定義字段: models.FloatField(..., max_digits=5, decimal_places=2) 要保存最大值一百萬(小數點後保存10位)的話,你要這樣定義: models.FloatField(..., max_digits=19, decimal_places=10) admin 用一個文本框(<input type="text">)表示該字段保存的數據. <4> AutoField 一個 IntegerField, 添加記錄時它會自動增加. 你一般不須要直接使用這個字段; 自定義一個主鍵:my_id=models.AutoField(primary_key=True) 若是你不指定主鍵的話,系統會自動添加一個主鍵字段到你的 model. <5> BooleanField A true/false field. admin 用 checkbox 來表示此類字段. <6> TextField 一個容量很大的文本字段. admin 用一個 <textarea> (文本區域)表示該字段數據.(一個多行編輯框). <7> EmailField 一個帶有檢查Email合法性的 CharField,不接受 maxlength 參數. <8> DateField 一個日期字段. 共有下列額外的可選參數: Argument 描述 auto_now 當對象被保存時,自動將該字段的值設置爲當前時間.一般用於表示 "last-modified" 時間戳. auto_now_add 當對象首次被建立時,自動將該字段的值設置爲當前時間.一般用於表示對象建立時間. <14> SlugField "Slug" 是一個報紙術語. slug 是某個東西的小小標記(短籤), 只包含字母,數字,下劃線和連字符.#它們一般用於URLs 若你使用 Django 開發版本,你能夠指定 maxlength. 若 maxlength 未指定, Django 會使用默認長度: 50. #在 之前的 Django 版本,沒有任何辦法改變50 這個長度. 這暗示了 db_index=True. 它接受一個額外的參數: prepopulate_from, which is a list of fields from which to auto-#populate the slug, via JavaScript,in the object's admin form: models.SlugField (prepopulate_from=("pre_name", "name"))prepopulate_from 不接受 DateTimeFields. <13> XMLField 一個校驗值是否爲合法XML的 TextField,必須提供參數: schema_path, 它是一個用來校驗文本的 RelaxNG schema #的文件系統路徑. <14> FilePathField 可選項目爲某個特定目錄下的文件名. 支持三個特殊的參數, 其中第一個是必須提供的. 參數 描述 path 必需參數. 一個目錄的絕對文件系統路徑. FilePathField 據此獲得可選項目. Example: "/home/images". match 可選參數. 一個正則表達式, 做爲一個字符串, FilePathField 將使用它過濾文件名. 注意這個正則表達式只會應用到 base filename 而不是 路徑全名. Example: "foo.*\.txt^", 將匹配文件 foo23.txt 卻不匹配 bar.txt 或 foo23.gif. recursive可選參數.要麼 True 要麼 False. 默認值是 False. 是否包括 path 下面的所有子目錄. 這三個參數能夠同時使用. match 僅應用於 base filename, 而不是路徑全名. 那麼,這個例子: FilePathField(path="/home/images", match="foo.*", recursive=True) ...會匹配 /home/images/foo.gif 而不匹配 /home/images/foo/bar.gif <15> IPAddressField 一個字符串形式的 IP 地址, (i.e. "24.124.1.30"). <16> CommaSeparatedIntegerField 用於存放逗號分隔的整數值. 相似 CharField, 必需要有maxlength參數.
更多參數:
(1)null 若是爲True,Django 將用NULL 來在數據庫中存儲空值。 默認值是 False. (1)blank 若是爲True,該字段容許不填。默認爲False。 要注意,這與 null 不一樣。null純粹是數據庫範疇的,而 blank 是數據驗證範疇的。 若是一個字段的blank=True,表單的驗證將容許該字段是空值。若是字段的blank=False,該字段就是必填的。 (2)default 字段的默認值。能夠是一個值或者可調用對象。若是可調用 ,每有新對象被建立它都會被調用。 (3)primary_key 若是爲True,那麼這個字段就是模型的主鍵。若是你沒有指定任何一個字段的primary_key=True, Django 就會自動添加一個IntegerField字段作爲主鍵,因此除非你想覆蓋默認的主鍵行爲, 不然不必設置任何一個字段的primary_key=True。 (4)unique 若是該值設置爲 True, 這個數據字段的值在整張表中必須是惟一的 (5)choices 由二元組組成的一個可迭代對象(例如,列表或元組),用來給字段提供選擇項。 若是設置了choices ,默認的表單將是一個選擇框而不是標準的文本框,<br>並且這個選擇框的選項就是choices 中的選項。
root@darren-virtual-machine:~/PycharmProjects/mysite# python3 manage.py makemigrations
報錯以下
MySQLclient目前只支持到python3.4,所以若是使用的更高版本的python,須要修改以下:
root@darren-virtual-machine:~/PycharmProjects/mysite# vim /usr/local/lib/python3.6/dist-packages/django/db/backends/mysql/base.py
#if version < (1, 3, 13): # raise ImproperlyConfigured('mysqlclient 1.3.13 or newer is required; you have %s.' % Database.__version__)
註釋掉 就OK了。
繼續執行
root@darren-virtual-machine:~/PycharmProjects/mysite# python3 manage.py makemigrations
Migrations for 'app01': app01/migrations/0001_initial.py - Create model Book
root@darren-virtual-machine:~/PycharmProjects/mysite# ll app01/migrations/
-rw-r--r-- 1 root root 739 4月 5 16:40 0001_initial.py -rw-r--r-- 1 root root 0 4月 5 14:11 __init__.py drwxr-xr-x 2 root root 4096 4月 5 16:40 __pycache__/
root@darren-virtual-machine:~/PycharmProjects/mysite# cat app01/migrations/0001_initial.py
# Generated by Django 3.0.5 on 2020-04-05 08:40 from django.db import migrations, models class Migration(migrations.Migration): initial = True dependencies = [ ] operations = [ migrations.CreateModel( name='Book', fields=[ ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')), ('title', models.CharField(max_length=32)), ('author', models.CharField(max_length=32)), ('publisher', models.CharField(max_length=32)), ('price', models.DecimalField(decimal_places=2, max_digits=5)), ('pub_date', models.DateField()), ], ), ]
root@darren-virtual-machine:~/PycharmProjects/mysite# python3 manage.py migrate
Operations to perform:
Apply all migrations: admin, app01, auth, contenttypes, sessions
Running migrations:
Applying contenttypes.0001_initial... OK
Applying auth.0001_initial... OK
Applying admin.0001_initial... OK
Applying admin.0002_logentry_remove_auto_add... OK
Applying admin.0003_logentry_add_action_flag_choices... OK
Applying app01.0001_initial... OK
Applying contenttypes.0002_remove_content_type_name... OK
Applying auth.0002_alter_permission_name_max_length... OK
Applying auth.0003_alter_user_email_max_length... OK
Applying auth.0004_alter_user_username_opts... OK
Applying auth.0005_alter_user_last_login_null... OK
Applying auth.0006_require_contenttypes_0002... OK
Applying auth.0007_alter_validators_add_error_messages... OK
Applying auth.0008_alter_user_username_max_length... OK
Applying auth.0009_alter_user_last_name_max_length... OK
Applying auth.0010_alter_group_name_max_length... OK
Applying auth.0011_update_proxy_permissions... OK
Applying sessions.0001_initial... OK
查看數據庫
mysql> show tables; +----------------------------+ | Tables_in_django | +----------------------------+ | app01_book | | auth_group | | auth_group_permissions | | auth_permission | | auth_user | | auth_user_groups | | auth_user_user_permissions | | django_admin_log | | django_content_type | | django_migrations | | django_session | +----------------------------+ 11 rows in set (0.00 sec) mysql> desc app01_book; +-----------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-----------+--------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | title | varchar(32) | NO | | NULL | | | author | varchar(32) | NO | | NULL | | | publisher | varchar(32) | NO | | NULL | | | price | decimal(5,2) | NO | | NULL | | | pub_date | date | NO | | NULL | | +-----------+--------------+------+-----+---------+----------------+
配置url
root@darren-virtual-machine:~/PycharmProjects/mysite# vim mysite/urls.py
from django.contrib import admin from django.urls import path,include urlpatterns = [ path('admin/', admin.site.urls), path('app01/', include("app01.urls")), ]
root@darren-virtual-machine:~/PycharmProjects/mysite# vim app01/urls.py
from django.urls import path,re_path from app01 import views urlpatterns = [ path('add_book/', views.add_book), ]
視圖文件
root@darren-virtual-machine:~/PycharmProjects/mysite# vim app01/views.py
from django.shortcuts import render,HttpResponse from app01 import models # Create your views here. def add_book(request): if request.method == "GET": return render(request,"add_book.html") else: #方式一:經過類實例化對象的方式。注意:必定要對象.save() title = request.POST.get("title") author = request.POST.get("author") publisher = request.POST.get("publisher") price = request.POST.get("price") pub_date = request.POST.get("pub_date") book_obj = models.Book(title=title,author=author,publisher=publisher,price=price,pub_date=pub_date) book_obj.save() return HttpResponse("新增成功")
html模板文件
建立templates目錄
root@darren-virtual-machine:~/PycharmProjects/mysite# mkdir templates
註冊template
root@darren-virtual-machine:~/PycharmProjects/mysite# vim mysite/settings.py
TEMPLATES = [ { 'BACKEND': 'django.template.backends.django.DjangoTemplates', 'DIRS': [os.path.join(BASE_DIR,"templates")], 'APP_DIRS': True, 'OPTIONS': { 'context_processors': [ 'django.template.context_processors.debug', 'django.template.context_processors.request', 'django.contrib.auth.context_processors.auth', 'django.contrib.messages.context_processors.messages', ], }, }, ]
root@darren-virtual-machine:~/PycharmProjects/mysite# vim templates/add_book.html
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <h3>新增書籍</h3> <form action="" method="post"> {% csrf_token %} <p>書名:<input type="text" name="title"></p> <p>做者:<input type="text" name="author"></p> <p>出版社:<input type="text" name="publisher"></p> <p>價格:<input type="text" name="price"></p> <p>出版時間:<input type="text" name="pub_date"></p> <input type="submit"> </form> </body> </html>
訪問http://127.0.0.1:8000/app01/add_book
提交
查看數據庫
mysql> select * from app01_book;
+----+-----------+-----------+-----------------+--------+------------+ | id | title | author | publisher | price | pub_date | +----+-----------+-----------+-----------------+--------+------------+ | 1 | 紅樓夢 | 曹雪芹 | 清華出版社 | 165.00 | 2018-12-12 | +----+-----------+-----------+-----------------+--------+------------+ 1 row in set (0.00 sec)
方式二:經過ORM提供的objects提供的方法 create來實現。
root@darren-virtual-machine:~/PycharmProjects/mysite# cat app01/views.py
from django.shortcuts import render,HttpResponse from app01 import models # Create your views here. def add_book(request): if request.method == "GET": return render(request,"add_book.html") else: #方式一: title = request.POST.get("title") author = request.POST.get("author") publisher = request.POST.get("publisher") price = request.POST.get("price") pub_date = request.POST.get("pub_date") #book_obj = models.Book(title=title,author=author,publisher=publisher,price=price,pub_date=pub_date) #book_obj.save() #方式二,推薦使用 book_obj = models.Book.objects.create(title=title,author=author,publisher=publisher,price=price,pub_date=pub_date)
訪問插入數據http://127.0.0.1:8000/app01/add_book
數據庫查看記錄
mysql> select * from app01_book;
+----+--------------+-----------+-----------------+--------+------------+ | id | title | author | publisher | price | pub_date | +----+--------------+-----------+-----------------+--------+------------+ | 1 | 紅樓夢 | 曹雪芹 | 清華出版社 | 165.00 | 2018-12-12 | | 2 | 三國演義 | 羅貫中 | 北大出版社 | 199.00 | 2018-12-23 | +----+--------------+-----------+-----------------+--------+------------+
<1> all(): 查詢全部結果 <2> filter(**kwargs): 它包含了與所給篩選條件相匹配的對象 <3> get(**kwargs): 返回與所給篩選條件相匹配的對象,返回結果有且只有一個, 若是符合篩選條件的對象超過一個或者沒有都會拋出錯誤。 <4> exclude(**kwargs): 它包含了與所給篩選條件不匹配的對象 <5> order_by(*field): 對查詢結果排序 <6> reverse(): 對查詢結果反向排序 <7> count(): 返回數據庫中匹配查詢(QuerySet)的對象數量。 <8> first(): 返回第一條記錄 <9> last(): 返回最後一條記錄 <10> exists(): 若是QuerySet包含數據,就返回True,不然返回False <11> values(*field): 返回一個ValueQuerySet——一個特殊的QuerySet,運行後獲得的並非一系列 model的實例化對象,而是一個可迭代的字典序列 <12> values_list(*field): 它與values()很是類似,它返回的是一個元組序列,values返回的是一個字典序列 <13> distinct(): 從返回結果中剔除重複紀錄
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="法") Book.objects.filter(title__icontains="python") # 不區分大小寫 Book.objects.filter(title__startswith="九") Book.objects.filter(pub_date__year=2018)
添加測試數據
root@darren-virtual-machine:~/PycharmProjects/mysite# cat app01/views.py
from django.shortcuts import render,HttpResponse from app01 import models # Create your views here. def add_book(request): if request.method == "GET": return render(request,"add_book.html") else: #方式一: title = request.POST.get("title") author = request.POST.get("author") publisher = request.POST.get("publisher") price = request.POST.get("price") pub_date = request.POST.get("pub_date") #book_obj = models.Book(title=title,author=author,publisher=publisher,price=price,pub_date=pub_date) #book_obj.save() #方式二,推薦使用 #book_obj = models.Book.objects.create(title=title,author=author,publisher=publisher,price=price,pub_date=pub_date) #添加數據,添加完成後,及時刪除 models.Book.objects.create(title="水滸傳",author="施耐庵",price=180, publisher="北電出版社", pub_date="2019-1-12") models.Book.objects.create(title="西遊記",author="吳承恩",price=185, publisher="北大出版社", pub_date="2019-2-12") models.Book.objects.create(title="獨孤九劍", author="風清揚",price = 190, publisher = "華山出版社", pub_date = "2019-1-15") models.Book.objects.create(title="葵花寶典", author="東方不敗", price=120, publisher="黑木崖出版社", pub_date="2019-1-20") models.Book.objects.create(title="易筋經", author="方丈大師", price=140, publisher="少林出版社", pub_date="2019-1-23") models.Book.objects.create(title="道德經", author="老子", price=176, publisher="北大出版社", pub_date="2019-2-23") models.Book.objects.create(title="論語", author="孔子弟子", price=165, publisher="北電出版社", pub_date="2019-2-13") models.Book.objects.create(title="九陽神功", author="張無忌", price=130, publisher="少林出版社", pub_date="2018-1-23") models.Book.objects.create(title="九陰真經", author="黃裳", price=145, publisher="大宋出版社", pub_date="2017-3-23") return HttpResponse("新增成功")
訪問http://127.0.0.1:8000/app01/add_book,點擊submit
查看數據庫
mysql> select * from app01_book;
mysql> select * from app01_book;
+----+--------------+--------------+--------------------+--------+------------+
| id | title | author | publisher | price | pub_date |
+----+--------------+--------------+--------------------+--------+------------+
| 1 | 紅樓夢 | 曹雪芹 | 清華出版社 | 165.00 | 2018-12-12 |
| 2 | 三國演義 | 羅貫中 | 北大出版社 | 199.00 | 2018-12-23 |
| 3 | 水滸傳 | 施耐庵 | 北電出版社 | 180.00 | 2019-01-12 |
| 4 | 西遊記 | 吳承恩 | 北大出版社 | 185.00 | 2019-02-12 |
| 5 | 獨孤九劍 | 風清揚 | 華山出版社 | 190.00 | 2019-01-15 |
| 6 | 葵花寶典 | 東方不敗 | 黑木崖出版社 | 120.00 | 2019-01-20 |
| 7 | 易筋經 | 方丈大師 | 少林出版社 | 140.00 | 2019-01-23 |
| 8 | 道德經 | 老子 | 北大出版社 | 176.00 | 2019-02-23 |
| 9 | 論語 | 孔子弟子 | 北電出版社 | 165.00 | 2019-02-13 |
| 10 | 九陽神功 | 張無忌 | 少林出版社 | 130.00 | 2018-01-23 |
| 11 | 九陰真經 | 黃裳 | 大宋出版社 | 145.00 | 2017-03-23 |
+----+--------------+--------------+--------------------+--------+------------+
必須恢復views.py,不然會重複添加
編輯路由
root@darren-virtual-machine:~/PycharmProjects/mysite# cat app01/urls.py
from django.urls import path,re_path from app01 import views urlpatterns = [ path('add_book/', views.add_book), path('query_book',views.query_book), ]
定義視圖函數
root@darren-virtual-machine:~/PycharmProjects/mysite# cat app01/views.py
from django.shortcuts import render,HttpResponse from app01 import models # Create your views here. def add_book(request): if request.method == "GET": return render(request,"add_book.html") else: #方式一: title = request.POST.get("title") author = request.POST.get("author") publisher = request.POST.get("publisher") price = request.POST.get("price") pub_date = request.POST.get("pub_date") #book_obj = models.Book(title=title,author=author,publisher=publisher,price=price,pub_date=pub_date) #book_obj.save() #方式二,推薦使用 book_obj = models.Book.objects.create(title=title,author=author,publisher=publisher,price=price,pub_date=pub_date) return HttpResponse("新增成功") def query_book(request): #all,獲取全部結果 books = models.Book.objects.all() print(books) return HttpResponse("查詢成功")
訪問http://127.0.0.1:8000/app01/query_book
輸出結果
[05/Apr/2020 11:59:21] "GET /app01/add_book/ HTTP/1.1" 200 618
<QuerySet [<Book: Book object (1)>, <Book: Book object (2)>, <Book: Book object (3)>, <Book: Book object (4)>, <Book: Book object (5)>, <Book: Book object (6)>, <Book: Book object (7)>, <Book: Book object (8)>, <Book: Book object (9)>, <Book: Book object (10)>, <Book: Book object (11)>]>
[05/Apr/2020 11:59:26] "GET /app01/query_book HTTP/1.1" 200 12
model返回一個title值
root@darren-virtual-machine:~/PycharmProjects/mysite# cat app01/models.py
from django.db import models # Create your models here. class Book(models.Model): title = models.CharField(max_length=32) author = models.CharField(max_length=32) publisher = models.CharField(max_length=32) price = models.DecimalField(max_digits=5, decimal_places=2) pub_date = models.DateField() def __str__(self): return self.title
再次訪問查看
[05/Apr/2020 12:04:48] "GET /app01/query_book HTTP/1.1" 200 12 <QuerySet [<Book: 紅樓夢>, <Book: 三國演義>, <Book: 水滸傳>, <Book: 西遊記>, <Book: 獨孤九劍>, <Book: 葵花寶典>, <Book: 易筋經>, <Book: 道德經>, <Book: 論語>, <Book: 九陽神功>, <Book: 九陰真經>]>
root@darren-virtual-machine:~/PycharmProjects/mysite# cat app01/views.py
from django.shortcuts import render,HttpResponse from app01 import models # Create your views here. def add_book(request): if request.method == "GET": return render(request,"add_book.html") else: #方式一: title = request.POST.get("title") author = request.POST.get("author") publisher = request.POST.get("publisher") price = request.POST.get("price") pub_date = request.POST.get("pub_date") #book_obj = models.Book(title=title,author=author,publisher=publisher,price=price,pub_date=pub_date) #book_obj.save() #方式二,推薦使用 book_obj = models.Book.objects.create(title=title,author=author,publisher=publisher,price=price,pub_date=pub_date) return HttpResponse("新增成功") def query_book(request): #filter Query 對象,相似於列表,獲取知足條件的對象,filter能夠知足多個條件,之間關係爲and books_filter = models.Book.objects.filter(pk=3) print(books_filter) #get,獲取對象,沒有結果或者有多個結果 會報錯 books_get = models.Book.objects.get(pk=3) print(books_get,type(books_get)) #exclude,query類型,和filter相反,排除知足條件的類型 books_exclude = models.Book.objects.exclude(pk=3) print(books_exclude) #order_by默認升序,降序前面添加-便可 books_order_by = models.Book.objects.order_by("price") print(books_order_by) books_order_by = models.Book.objects.order_by("-price") print(books_order_by) #reverse books_reverse = models.Book.objects.order_by("-price").reverse() print(books_reverse) #first獲取第一條 book_first= models.Book.objects.filter(pk=4).first() print(book_first) #exist判斷結果是否訊在,存在返回true books_exist = models.Book.objects.exclude(pk=4) print(books_exist,type(books_exist)) #vaules,QUeryset類型,相似於字典 books_vaules = models.Book.objects.values("title","price") print(books_vaules,type(books_vaules)) # vaules_list,QUeryset類型,相似於元祖 books_vaules1 = models.Book.objects.values_list("title","price") print(books_vaules1,type(books_vaules1)) #distinct,去除重複 books = models.Book.objects.values("publisher").distinct() print(books,type(books)) return HttpResponse("查詢成功")
查詢結果
<QuerySet [<Book: 水滸傳>]> 水滸傳 <class 'app01.models.Book'> <QuerySet [<Book: 紅樓夢>, <Book: 三國演義>, <Book: 西遊記>, <Book: 獨孤九劍>, <Book: 葵花寶典>, <Book: 易筋經>, <Book: 道德經>, <Book: 論語>, <Book: 九陽神功>, <Book: 九陰真經>]> <QuerySet [<Book: 葵花寶典>, <Book: 九陽神功>, <Book: 易筋經>, <Book: 九陰真經>, <Book: 紅樓夢>, <Book: 論語>, <Book: 道德經>, <Book: 水滸傳>, <Book: 西遊記>, <Book: 獨孤九劍>, <Book: 三國演義>]> <QuerySet [<Book: 三國演義>, <Book: 獨孤九劍>, <Book: 西遊記>, <Book: 水滸傳>, <Book: 道德經>, <Book: 紅樓夢>, <Book: 論語>, <Book: 九陰真經>, <Book: 易筋經>, <Book: 九陽神功>, <Book: 葵花寶典>]> <QuerySet [<Book: 葵花寶典>, <Book: 九陽神功>, <Book: 易筋經>, <Book: 九陰真經>, <Book: 紅樓夢>, <Book: 論語>, <Book: 道德經>, <Book: 水滸傳>, <Book: 西遊記>, <Book: 獨孤九劍>, <Book: 三國演義>]> 西遊記 <QuerySet [<Book: 紅樓夢>, <Book: 三國演義>, <Book: 水滸傳>, <Book: 獨孤九劍>, <Book: 葵花寶典>, <Book: 易筋經>, <Book: 道德經>, <Book: 論語>, <Book: 九陽神功>, <Book: 九陰真經>]> <class 'django.db.models.query.QuerySet'> <QuerySet [{'title': '紅樓夢', 'price': Decimal('165.00')}, {'title': '三國演義', 'price': Decimal('199.00')}, {'title': '水滸傳', 'price': Decimal('180.00')}, {'title': '西遊記', 'price': Decimal('185.00')}, {'title': '獨孤九劍', 'price': Decimal('190.00')}, {'title': '葵花寶典', 'price': Decimal('120.00')}, {'title': '易筋經', 'price': Decimal('140.00')}, {'title': '道德經', 'price': Decimal('176.00')}, {'title': '論語', 'price': Decimal('165.00')}, {'title': '九陽神功', 'price': Decimal('130.00')}, {'title': '九陰真經', 'price': Decimal('145.00')}]> <class 'django.db.models.query.QuerySet'> <QuerySet [('紅樓夢', Decimal('165.00')), ('三國演義', Decimal('199.00')), ('水滸傳', Decimal('180.00')), ('西遊記', Decimal('185.00')), ('獨孤九劍', Decimal('190.00')), ('葵花寶典', Decimal('120.00')), ('易筋經', Decimal('140.00')), ('道德經', Decimal('176.00')), ('論語', Decimal('165.00')), ('九陽神功', Decimal('130.00')), ('九陰真經', Decimal('145.00'))]> <class 'django.db.models.query.QuerySet'> <QuerySet [{'publisher': '清華出版社'}, {'publisher': '北大出版社'}, {'publisher': '北電出版社'}, {'publisher': '華山出版社'}, {'publisher': '黑木崖出版社'}, {'publisher': '少林出版社'}, {'publisher': '大宋出版社'}]> <class 'django.db.models.query.QuerySet'> [05/Apr/2020 12:37:56] "GET /app01/query_book HTTP/1.1" 200 1
刪除方法就是 delete()。它運行時當即刪除對象而不返回任何值。例如:
model_obj.delete()
你也能夠一次性刪除多個對象。每一個 QuerySet 都有一個 delete() 方法,它一次性刪除 QuerySet 中全部的對象。
例如,下面的代碼將刪除 pub_date 是2018年的 Book 對象:
Book.objects.filter(pub_date__year=2018).delete()
設計url
from django.urls import path,re_path from app01 import views urlpatterns = [ path('add_book/', views.add_book), #新增操做 path('query_book/',views.query_book), #查詢錯作 path('del_book/',views.del_book) #刪除操做 ]
視圖函數
root@darren-virtual-machine:~/PycharmProjects/mysite# cat app01/views.py
from django.shortcuts import render,HttpResponse from app01 import models # Create your views here. def add_book(request): if request.method == "GET": return render(request,"add_book.html") else: #方式一: title = request.POST.get("title") author = request.POST.get("author") publisher = request.POST.get("publisher") price = request.POST.get("price") pub_date = request.POST.get("pub_date") #book_obj = models.Book(title=title,author=author,publisher=publisher,price=price,pub_date=pub_date) #book_obj.save() #方式二,推薦使用 book_obj = models.Book.objects.create(title=title,author=author,publisher=publisher,price=price,pub_date=pub_date) return HttpResponse("新增成功") def query_book(request): #基於雙線劃線的模糊查詢 books = models.Book.objects.filter(price_in=[120,160,150]) print(books) books = models.Book.objects.filter(price_range=[120, 160]) print(books) return HttpResponse("查詢成功") def del_book(request): pk = request.GET.get('pk') print(pk) #方式一使用對象的形式刪除 book_obj = models.Book.objects.filter(pk=pk).first() book_obj.delete() return HttpResponse("刪除成功")
訪問http://127.0.0.1:8000/app01/del_book/?pk=3
查看數據庫
mysql> select * from app01_book;
+----+--------------+--------------+--------------------+--------+------------+ | id | title | author | publisher | price | pub_date | +----+--------------+--------------+--------------------+--------+------------+ | 1 | 紅樓夢 | 曹雪芹 | 清華出版社 | 165.00 | 2018-12-12 | | 2 | 三國演義 | 羅貫中 | 北大出版社 | 199.00 | 2018-12-23 | | 4 | 西遊記 | 吳承恩 | 北大出版社 | 185.00 | 2019-02-12 | | 5 | 獨孤九劍 | 風清揚 | 華山出版社 | 190.00 | 2019-01-15 | | 6 | 葵花寶典 | 東方不敗 | 黑木崖出版社 | 120.00 | 2019-01-20 | | 7 | 易筋經 | 方丈大師 | 少林出版社 | 140.00 | 2019-01-23 | | 8 | 道德經 | 老子 | 北大出版社 | 176.00 | 2019-02-23 | | 9 | 論語 | 孔子弟子 | 北電出版社 | 165.00 | 2019-02-13 | | 10 | 九陽神功 | 張無忌 | 少林出版社 | 130.00 | 2018-01-23 | | 11 | 九陰真經 | 黃裳 | 大宋出版社 | 145.00 | 2017-03-23 | +----+--------------+--------------+--------------------+--------+------------+
方法二
視圖函數
root@darren-virtual-machine:~/PycharmProjects/mysite# cat app01/views.py
。。。。。。 def del_book(request): pk = request.GET.get('pk') print(pk) #方式一使用對象的形式刪除 #book_obj = models.Book.objects.filter(pk=pk).first() #book_obj.delete() #方式二 books = models.Book.objects.filter(pk=pk).delete() #返回值是受影響的行數 print(books) return HttpResponse("刪除成功"
在 Django 刪除對象時,會模仿 SQL 約束 ON DELETE CASCADE 的行爲,換句話說,刪除一個對象時也會刪除與它相關聯的外鍵對象。例如:
b = Book.objects.get(pk=1) # This will delete the Blog and all of its Entry objects. b.delete()
要注意的是: delete() 方法是 QuerySet 上的方法,但並不適用於 Manager 自己。這是一種保護機制,是爲了不意外地調用 Entry.objects.delete() 方法致使 全部的 記錄被誤刪除。若是你確認要刪除全部的對象,那麼你必須顯式地調用:
Book.objects.all().delete()
訪問http://127.0.0.1:8000/app01/del_book/?pk=4
mysql> select * from app01_book;
+----+--------------+--------------+--------------------+--------+------------+ | id | title | author | publisher | price | pub_date | +----+--------------+--------------+--------------------+--------+------------+ | 1 | 紅樓夢 | 曹雪芹 | 清華出版社 | 165.00 | 2018-12-12 | | 2 | 三國演義 | 羅貫中 | 北大出版社 | 199.00 | 2018-12-23 | | 5 | 獨孤九劍 | 風清揚 | 華山出版社 | 190.00 | 2019-01-15 | | 6 | 葵花寶典 | 東方不敗 | 黑木崖出版社 | 120.00 | 2019-01-20 | | 7 | 易筋經 | 方丈大師 | 少林出版社 | 140.00 | 2019-01-23 | | 8 | 道德經 | 老子 | 北大出版社 | 176.00 | 2019-02-23 | | 9 | 論語 | 孔子弟子 | 北電出版社 | 165.00 | 2019-02-13 | | 10 | 九陽神功 | 張無忌 | 少林出版社 | 130.00 | 2018-01-23 | | 11 | 九陰真經 | 黃裳 | 大宋出版社 | 145.00 | 2017-03-23 | +----+--------------+--------------+--------------------+--------+------------+
調試輸出
4 (1, {'app01.Book': 1}) [05/Apr/2020 13:26:15] "GET /app01/del_book/?pk=4 HTTP/1.1" 200 12
設計url
from django.urls import path,re_path from app01 import views urlpatterns = [ path('add_book/', views.add_book), #新增操做 path('query_book/',views.query_book), #查詢錯作 path('del_book/',views.del_book), #刪除操做 path('edit_book/',views.edit_book), #編輯操做 ]
視圖函數
from django.shortcuts import render,HttpResponse from app01 import models # Create your views here. def add_book(request): if request.method == "GET": return render(request,"add_book.html") else: #方式一: title = request.POST.get("title") author = request.POST.get("author") publisher = request.POST.get("publisher") price = request.POST.get("price") pub_date = request.POST.get("pub_date") #book_obj = models.Book(title=title,author=author,publisher=publisher,price=price,pub_date=pub_date) #book_obj.save() #方式二,推薦使用 book_obj = models.Book.objects.create(title=title,author=author,publisher=publisher,price=price,pub_date=pub_date) return HttpResponse("新增成功") def query_book(request): #基於雙線劃線的模糊查詢 books = models.Book.objects.filter(price_in=[120,160,150]) print(books) books = models.Book.objects.filter(price_range=[120, 160]) print(books) return HttpResponse("查詢成功") def del_book(request): pk = request.GET.get('pk') print(pk) #方式一使用對象的形式刪除 #book_obj = models.Book.objects.filter(pk=pk).first() #book_obj.delete() #方式二 books = models.Book.objects.filter(pk=pk).delete() print(books) return HttpResponse("刪除成功") def edit_book(request): pk = request.GET.get("pk") if request.method == "GET": book_obj = models.Book.objects.filter(pk=pk).first() return render(request,"edit_book.html",{"book_obj":book_obj})
html模板文件
root@darren-virtual-machine:~/PycharmProjects/mysite# cat templates/edit_book.html
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <h3>編輯數據</h3> <form action="" method="post"> {% csrf_token %} <p>書名:<input type="text" name="title" value="{{ book_obj.title }}"></p> <p>做者:<input type="text" name="author" value="{{ book_obj.author }}"></p> <p>出版社:<input type="text" name="publisher" value="{{ book_obj.publisher }}"></p> <p>價格:<input type="text" name="price" value="{{ book_obj.price }}"></p> <p>出版時間:<input type="text" name="pub_date" value="{{ book_obj.pub_date|date:"Y-m-d" }}"></p> <input type="submit"> </form> </body> </html>
訪問http://127.0.0.1:8000/app01/edit_book/?pk=5
修改顯示時間
<form action="" method="post"> {% csrf_token %} <p>書名:<input type="text" name="title" value="{{ book_obj.title }}"></p> <p>做者:<input type="text" name="author" value="{{ book_obj.author }}"></p> <p>出版社:<input type="text" name="publisher" value="{{ book_obj.publisher }}"></p> <p>價格:<input type="text" name="price" value="{{ book_obj.price }}"></p> <p>出版時間:<input type="text" name="pub_date" value="{{ book_obj.pub_date|date:"Y-m-d" }}"></p> <input type="submit"> </form>
刷新
編輯操做
方式一:
經過修改實例對象的屬性方式。注意:必定要對象.save()
def edit_book(request): pk = request.GET.get("pk") if request.method == "GET": book_obj = models.Book.objects.filter(pk=pk).first() return render(request,"edit_book.html",{"book_obj":book_obj}) else: #方式一: title = request.POST.get("title") author = request.POST.get("author") publisher = request.POST.get("publisher") price = request.POST.get("price") pub_date = request.POST.get("pub_date") book_obj = models.Book.objects.filter(pk=pk).first() book_obj.price = price book_obj.save() return HttpResponse("編輯成功")
訪問http://127.0.0.1:8000/app01/edit_book/?pk=5並修改
數據庫查詢
+----+--------------+--------------+--------------------+--------+------------+
| id | title | author | publisher | price | pub_date |
+----+--------------+--------------+--------------------+--------+------------+
| 1 | 紅樓夢 | 曹雪芹 | 清華出版社 | 165.00 | 2018-12-12 |
| 2 | 三國演義 | 羅貫中 | 北大出版社 | 199.00 | 2018-12-23 |
| 5 | 獨孤九劍 | 風清揚 | 華山出版社 | 143.00 | 2019-01-15 |
| 6 | 葵花寶典 | 東方不敗 | 黑木崖出版社 | 120.00 | 2019-01-20 |
| 7 | 易筋經 | 方丈大師 | 少林出版社 | 140.00 | 2019-01-23 |
| 8 | 道德經 | 老子 | 北大出版社 | 176.00 | 2019-02-23 |
| 9 | 論語 | 孔子弟子 | 北電出版社 | 165.00 | 2019-02-13 |
| 10 | 九陽神功 | 張無忌 | 少林出版社 | 130.00 | 2018-01-23 |
| 11 | 九陰真經 | 黃裳 | 大宋出版社 | 145.00 | 2017-03-23 |
+----+--------------+--------------+--------------------+--------+------------+
方式二:
經過ORM提供的objects提供的方法 update來實現。
from django.shortcuts import render,HttpResponse from app01 import models # Create your views here. def add_book(request): if request.method == "GET": return render(request,"add_book.html") else: #方式一: title = request.POST.get("title") author = request.POST.get("author") publisher = request.POST.get("publisher") price = request.POST.get("price") pub_date = request.POST.get("pub_date") #book_obj = models.Book(title=title,author=author,publisher=publisher,price=price,pub_date=pub_date) #book_obj.save() #方式二,推薦使用 book_obj = models.Book.objects.create(title=title,author=author,publisher=publisher,price=price,pub_date=pub_date) return HttpResponse("新增成功") def query_book(request): #基於雙線劃線的模糊查詢 books = models.Book.objects.filter(price_in=[120,160,150]) print(books) books = models.Book.objects.filter(price_range=[120, 160]) print(books) return HttpResponse("查詢成功") def del_book(request): pk = request.GET.get('pk') print(pk) #方式一使用對象的形式刪除 #book_obj = models.Book.objects.filter(pk=pk).first() #book_obj.delete() #方式二 books = models.Book.objects.filter(pk=pk).delete() print(books) return HttpResponse("刪除成功") def edit_book(request): pk = request.GET.get("pk") if request.method == "GET": book_obj = models.Book.objects.filter(pk=pk).first() return render(request,"edit_book.html",{"book_obj":book_obj}) else: #方式二: title = request.POST.get("title") author = request.POST.get("author") publisher = request.POST.get("publisher") price = request.POST.get("price") pub_date = request.POST.get("pub_date") books = models.Book.objects.filter(pk=pk).update(price=price) #返回影響事物的行數 print(books) return HttpResponse("編輯成功")
此外,update()方法對於任何結果集(QuerySet)均有效,這意味着你能夠同時更新多條記錄update()方法會返回一個整型數值,表示受影響的記錄條數。
訪問 http://127.0.0.1:8000/app01/edit_book/?pk=6並修改
查看數據庫
mysql> select * from app01_book; +----+--------------+--------------+--------------------+--------+------------+ | id | title | author | publisher | price | pub_date | +----+--------------+--------------+--------------------+--------+------------+ | 1 | 紅樓夢 | 曹雪芹 | 清華出版社 | 165.00 | 2018-12-12 | | 2 | 三國演義 | 羅貫中 | 北大出版社 | 199.00 | 2018-12-23 | | 5 | 獨孤九劍 | 風清揚 | 華山出版社 | 143.00 | 2019-01-15 | | 6 | 葵花寶典 | 東方不敗 | 黑木崖出版社 | 179.00 | 2019-01-20 | | 7 | 易筋經 | 方丈大師 | 少林出版社 | 140.00 | 2019-01-23 | | 8 | 道德經 | 老子 | 北大出版社 | 176.00 | 2019-02-23 | | 9 | 論語 | 孔子弟子 | 北電出版社 | 165.00 | 2019-02-13 | | 10 | 九陽神功 | 張無忌 | 少林出版社 | 130.00 | 2018-01-23 | | 11 | 九陰真經 | 黃裳 | 大宋出版社 | 145.00 | 2017-03-23 | +----+--------------+--------------+--------------------+--------+------------+
編輯成功