python 之 Django 小案例
一, F Q
# F 使用查询条件的值 # # from django.db.models import F # models.Tb1.objects.update(num=F('num')+1) # Q 构建搜索条件 from django.db.models import Q # con = Q() # # q1 = Q() # q1.connector = 'OR' # q1.children.append(('id', 1)) # q1.children.append(('id', 10)) # q1.children.append(('id', 9)) # # q2 = Q() # q2.connector = 'OR' # q2.children.append(('c1', 1)) # q2.children.append(('c1', 10)) # q2.children.append(('c1', 9)) # # con.add(q1, 'AND') # con.add(q2, 'AND') # # models.Tb1.objects.filter(con) # # from django.db import connection # cursor = connection.cursor() # cursor.execute("""SELECT * from tb where name = %s""", ['Lennon']) # row = cursor.fetchone()
Django基于Q 实现ajax请求数据库
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <style> .left{ float: left; } .clearfix:after{ content: '.'; clear: both; display: block; visibility: hidden; height: 0; } </style> </head> <body> <div class="condition"> <div class="item clearfix"> <div class="icon left" onclick="AddCondition(this);">+</div> <div class="left"> <select onchange="ChangeName(this);"> <option value="name">书名</option> <option value="book_type__caption">图书类型</option> <option value="price">价格</option> <option value="pages">页数</option> </select> </div> <div class="left"><input type="text" name="name" /></div> </div> </div> <div> <input type="button" onclick="Search();" value="搜索" /> </div> <div class="container"> </div> <script src="/static/jquery-1.9.1.min.js"></script> <script> function AddCondition(ths) { var new_tag = $(ths).parent().clone(); new_tag.find('.icon').text('-'); new_tag.find('.icon').attr('onclick', 'RemoveCondition(this);'); $(ths).parent().parent().append(new_tag); } function RemoveCondition(ths) { $(ths).parent().remove(); } function ChangeName(ths) { var v = $(ths).val(); $(ths).parent().next().find('input').attr('name',v); } function Search() { var post_data_dict = {}; // 获取所有input的内容，提交数据 $('.condition input').each(function () { // console.log($(this)[0]) var n = $(this).attr('name'); var v = $(this).val(); var v_list = v.split('，'); post_data_dict[n] = v_list; }); console.log(post_data_dict); var post_data_str = JSON.stringify(post_data_dict); $.ajax({ url: '/index/', type: 'POST', data: { 'post_data': post_data_str}, dataType: 'json', success: function (arg) { // 字符串 "<table>" + if(arg.status){ var table = document.createElement('table'); table.setAttribute('border',1); // [{,name,pubdate,price,caption},] $.each(arg.data, function(k,v){ var tr = document.createElement('tr'); var td1 = document.createElement('td'); td1.innerText = v['name']; var td2 = document.createElement('td'); td2.innerText = v['price']; var td3 = document.createElement('td'); td3.innerText = v['book_type__caption']; var td4 = document.createElement('td'); td4.innerText = v['pubdate']; tr.appendChild(td1); tr.appendChild(td2); tr.appendChild(td3); tr.appendChild(td4); table.appendChild(tr); }); $('.container').empty(); $('.container').append(table); }else{ alert(arg.message); } } }) } </script> </body> </html>
from django.shortcuts import render,HttpResponse from app01 import models # Create your views here. import json def test(request): # models.BookType.objects.create(caption='技术') # models.BookType.objects.create(caption='文学') # models.BookType.objects.create(caption='动漫') # models.BookType.objects.create(caption='男人装') # models.Book.objects.create(name='文艺复兴',pages='100',price='40',pubdate='1992-11-2',book_type_id='1') # models.Book.objects.create(name='解密',pages='80',price='10', pubdate='2016-6-10',book_type_id='2') # models.Book.objects.create(name='刀锋',pages='50',price='3', pubdate='2014-02-16',book_type_id='2') # models.Book.objects.create(name='查令十字路84号',pages='260',price='40',pubdate='1999-10-12',book_type_id='3') # models.Book.objects.create(name='红楼',pages='1000',price='500', pubdate='1760-1-1',book_type_id='3') # models.Book.objects.create(name='将夜',pages='2000',price='300', pubdate='2010-3-3',book_type_id='1') # models.Book.objects.create(name='mysql从删库到跑路',pages='20',price='10',pubdate='1998-9-2',book_type_id='4') # models.Book.objects.create(name='马克思主义',pages='50',price='100',pubdate='1937-3-3',book_type_id='2') return HttpResponse('ok') import json from datetime import date from datetime import datetime from decimal import Decimal class JsonCustomEncoder(json.JSONEncoder): def default(self, field): if isinstance(field, datetime): return field.strftime('%Y-%m-%d %H:%M:%S') elif isinstance(field, date): return field.strftime('%Y-%m-%d') elif isinstance(field, Decimal): return str(field) else: return json.JSONEncoder.default(self, field) def index(request): if request.method == 'POST': print(request.POST.get('post_data',None)) ret = {'status': False, 'message': '', 'data':None} try: post_data = request.POST.get('post_data',None) post_data_dict = json.loads(post_data) print(post_data_dict,type(post_data_dict)) # {'name': ['11', 'sdf']，'price': ['11', 'sdf']} # 构造搜索条件 from django.db.models import Q con = Q() for k,v in post_data_dict.items(): q = Q() q.connector = 'OR' for item in v: print(v,type(v)) q.children.append((k, item)) con.add(q, 'AND') """ ret = models.Book.objects.filter(con) print(ret) # queryset,[对象] from django.core import serializers data = serializers.serialize("json", ret) print(type(data),data) # 字符串 """ """ # ret = models.Book.objects.filter(con).values('name','book_type__caption')# 列表里面以字典的形式 # #ret = models.Book.objects.filter(con).values_list('name', 'book_type__caption')# 列表里面以元组的形式 # # li = list(ret) # data = json.dumps(li) # print(data,type(data)) """ result = models.Book.objects.filter(con).values('name','price','pubdate','book_type__caption') # ret = models.Book.objects.filter(con).values_list('name', 'book_type__caption') li = list(result) ret['status'] = True ret['data'] = li except Exception as e: ret['message'] = str(e) ret_str = json.dumps(ret, cls=JsonCustomEncoder) return HttpResponse(ret_str) return render(request, 'index.html')
from django.db import models # Create your models here. class Author(models.Model): name = models.CharField(max_length=20) age = models.IntegerField() class BookType(models.Model): caption = models.CharField(max_length=64) class Book(models.Model): name = models.CharField(max_length=64) pages = models.IntegerField() price = models.DecimalField(max_digits=10, decimal_places=2) pubdate = models.DateField() book_type = models.ForeignKey(BookType)
# 注意这个 是django自带的序列化 但是它不支持时间 小数等格式 ret = models.Book.objects.filter(con) print(ret) # queryset,[对象] from django.core import serializers data = serializers.serialize("json", ret) print(type(data),data)
# 字符串 这是通过 映射 取到值 """ """ # ret = models.Book.objects.filter(con).values('name','book_type__caption')# 列表里面以字典的形式 # #ret = models.Book.objects.filter(con).values_list('name', 'book_type__caption')# 列表里面以元组的形式 # # li = list(ret) # data = json.dumps(li) # print(data,type(data))
