Python學習第150天(目前正在做的內容介紹)
阿新 • • 發佈:2020-08-11
目前正在按照相關教程製作一個具有班級、學生、老師三者之間相互關係的網頁操作。目前暫時完成學生和班級部分內容,最為關鍵的manytomany班級與老師之間的關係還沒有完善,這個小例子對實際操作的過程使用非常有幫助,以下是近期程式碼內容:
model.py
from django.db import models class Classes(models.Model): # 班級表 titile = models.CharField(max_length=32) m = models.ManyToManyField('Teachers') class Teachers(models.Model): # 老師表 name= models.CharField(max_length=36) class Students(models.Model): username = models.CharField(max_length=32) age = models.IntegerField() gender = models.BooleanField() cs = models.ForeignKey(Classes, on_delete=None)
url.py
from django.contrib import admin from django.urls import path,re_pathfrom app01.views import classes from app01.views import students urlpatterns = [ path('admin/', admin.site.urls), re_path('^classes.html$',classes.get_classes), re_path('^add_classes.html$',classes.add_classes), re_path('^del_classes.html$',classes.del_classes), re_path('^edit_classes.html$',classes.edit_classes), re_path('^students.html$',students.get_students), re_path('^add_students.html$',students.add_studens), re_path('^del_students.html$',students.del_students), re_path('^edit_students.html$',students.edit_students) # re_path('^set_teacher.html$',classes.set_teacher), # path('a',classes.a_test), # path('b',classes.b_test), ]
classes.py
from django.shortcuts import render from django.shortcuts import redirect from app01 import models def get_classes(req): cls_list = models.Classes.objects.all() for item in cls_list: print(item.id,item.titile,item.m.all()) return render(req,'get_classes.html',{'cls_list':cls_list}) def add_classes(req): if req.method == 'GET': return render(req,'add_classes.html') elif req.method == 'POST': title = req.POST.get('title') models.Classes.objects.create(titile = title) return redirect('/classes.html') def del_classes(req): nid = req.GET.get('nid') print(nid) models.Classes.objects.filter(id=nid).delete() return redirect('/classes.html') def edit_classes(req): if req.method == 'GET': nid = req.GET.get('nid') obj = models.Classes.objects.filter(id=nid).first() return render(req,'edit_classes.html',{'obj':obj}) elif req.method == 'POST': nid = req.GET.get('nid') title = req.POST.get('xoxo') models.Classes.objects.filter(id=nid).update(titile = title) return redirect('/classes.html')
students.py
from django.shortcuts import render,redirect from app01 import models def get_students(req): stu_list = models.Students.objects.all() return render(req,'get_students.html',{'stu_list':stu_list}) def add_studens(req): if req.method == 'GET': cs_list = models.Classes.objects.all() return render(req,'add_students.html',{'cs_list':cs_list}) elif req.method == 'POST': u = req.POST.get('username') a = req.POST.get('age') g = req.POST.get('gender') c = req.POST.get('cs') print(u,a,g,c) models.Students.objects.create( username=u, age=a, gender=g, cs_id=c ) return redirect('/students.html') def del_students(req): nid = req.GET.get('nid') models.Students.objects.filter(id=nid).delete() return redirect('/students.html') def edit_students(req): if req.method == 'GET': nid = req.GET.get('nid') obj = models.Students.objects.filter(id=nid).first() cs_list = models.Classes.objects.all() return render(req, 'edit_students.html', {'obj': obj,'cs_list':cs_list}) elif req.method == 'POST': nid = req.GET.get('nid') cs_list = models.Classes.objects.all() # title = req.POST.get('xoxo') u = req.POST.get('username') a = req.POST.get('age') g = req.POST.get('gender') c = req.POST.get('c') models.Students.objects.filter(id=nid).update( username=u, age=a, gender=g, cs_id=c ) return redirect('/students.html')
其中最為關鍵的一個檢視模板
edit_students.html的內容
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <form action="edit_students.html?nid={{ obj.id }}" method="POST"> {% csrf_token %} {# <p style="display: none"> <input type="text" name="id" value="{{ obj.id }}" /></p>#} <p> <input type="text" name="username" value="{{ obj.username }}" /></p> <p> <input type="text" name="age" value="{{ obj.age }}" /></p> <p> {% if obj.gender %} 男:<input type="radio" name="gender" checked="checked" value="1" /> 女:<input type="radio" name="gender" value="0" /> {% else %} 男:<input type="radio" name="gender" value="1" /> 女:<input type="radio" name="gender" value="0" checked="checked" /> {% endif %} </p> <p> <select name="c"> {% for row in cs_list %} <option value="{{ row.id }}">{{ row.titile }}</option> {% endfor %} </select> </p> <input type="submit" value="提交" /> </form> </body> </html>
目前已經完成了基本功能,完整功能還是等這個部分全部做完後進行詳述。
關鍵的幾個注意點:
1. 類代表資料庫表
2. 類的物件代指資料庫的一行記錄
3.ForeignKey欄位代指關聯表中的一行資料(類的物件)
4.
- 正向:fk欄位 (*****)
- 反向:小寫類名_set(預設) ==> related_name='ssss'
5. 誰是主表?就全部列出其資料
models.Student.objects.all().values('username', 'cs__titile')
models.Classes.objects.all().values('titile', 'ssss__username')
4. M2M欄位,自動生成第三張表;依賴關聯表對第三張表間接操作
5.filter在查詢的過程中涉及外來鍵,可使用雙下劃線不斷向下查詢
以上為目前暫時更新的內容。