04.14 Edit and convert json format classes, jeasyui connects to database editing

Converting json can only be in the form of a dictionary, and individual objects cannot be converted

Recursion: call yourself by yourself. If you don't know how many layers you have with a loop, it's hard to control.

Fibonacci:

def b(n):
     if n== 2 or n== 1 :
         return 1
 return b(n- 1 )+b(n- 2 ) #n:2 b(1)+b(0)=2
 num= int ( input ( 'Please enter a positive integer:' ))    
res=b(num)
print(res)

The model is divided into two categories: classification table and commodity table.

from django.db import models
from datetime import datetime
# Create your models here.
#分类表
class Category(models.Model):
    cname=models.CharField(max_length=30,null=False)
    parent=models.ForeignKey('Category',on_delete=None)
    class Meta():
        db_table= 'category'
 #Goods table
 class Goods(models.Model):
    gname=models.CharField(max_length=50,null=False)
    price=models.FloatField()
    sum=models.IntegerField() #stock count
     =models.IntegerField() #stock quantity
     createTime=models.DateTimeField( default =datetime.now()) #stock time
     category=models.ForeignKey( 'Category' , on_delete = None )
     class Meta():
        db_table='Goods'

To convert an object to json, first convert it to a dictionary:

from django.shortcuts import render,HttpResponse
import json
from django.views.decorators.csrf import csrf_exempt
import pymysql
from .models import Category,Goods
from datetime import datetime
# Create your views here.
@csrf_exempt#导入csrf
def queryTree(request):
    id = request.POST.get( 'id' ) #Get the product id
 global categorySet #Get the global variable
 if id is None : #Just entered, no point, display the parent tree
 categorySet = Category.objects.filter( parent_id = None )
     else :                
        categorySet = Category.objects.filter( parent_id =id) #Click on the parent tree, the subset will come out
     list=[] #Edit json format
 for category in categorySet:    
        dict={}
        dict['id']=category.id
        dict[ 'text' ]=category.cname
         #if len(Category.objects.filter(parent_id=dict['id']))>0:#If there is a subset below, close it and display the file
         dict[ 'state' ]= 'closed'
         list.append(dict)

#     jsondata=[{
#  "id":1,
#  "text":"My Documents",
#         'state':'closed'},{
#     "id":2,
#     "text":"python5",
#         'state': 'closed',
#         'children':[
#             {
#                 'id':11,
#                 'text':'c1'
#             },
#             {
#                 'id': 22,
#                 'text': 'c2'
#             }
#         ]
# }]
return HttpResponse(json.dumps(list))    


#Load tree
 @csrf_exempt
 def queryGrid(request):
    goodsSet=Goods.objects.all() #queryset is a query set, which is a list of each object
     gridJson={ 'total' :Goods.objects.count()}
    list=[]
    for goods in goodsSet:#拼接
        dict={}
        dict['id']=goods.id
        dict['gname']=goods.gname
        dict['price']=goods.price
        dict['sum']=goods.sum
        dict['count']=goods.count
        dict['createTime']=datetime.strftime(goods.createTime,'%Y-%m-%d %H:%M:%S')
        list.append(dict)
    gridJson[ 'rows' ]=list
     #gridJson={#Find the style first, write according to the style, query the format through the small green book, look at the path, go to the folder to find, look at the format
     # 'total':3,'rows': [
     # {
     # 'code':'a10','name':'beer','price':4
     # },
     # {
     # 'code': 'a11', 'name': 'wine', 'price' : 84
     # },
     # {
     # 'code': 'a12', 'name': 'cookie', 'price': 14
     # },
     # ]
     # }
 return HttpResponse(json.dumps(gridJson)) #returning json Format