Django 数据库表单查询

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from django.shortcuts import renderfrom django.http import HttpResponsefrom django.template import loader,Contextfrom blog.models import Person# Create your views here.def student_list(request):    t = loader.get_template('student_list.html')    #studentList = Person.objects.all().order_by('age')  #过滤    studentList = Person.objects.all().filter(age__gt = 18)  #tiaojian > 18 (age = 18) = 18 (age__gte = 18) >= 18    c = Context({ 'studentList':studentList })    return HttpResponse(t.render(c))

常用查询函数：
get() 获取单个符合条件的，没有获取到返回空获取到多个报错
all() 获取所有符合条件的
filter() 等于，filter(a = ‘222’) 筛选出a = ‘222’ filter(name__in = [‘xiaoming’,’xiaohong’])
exclide() 于filter相反
order_by() 排序，对上面筛选到的结果进行排序order_by(‘-age’) 逆向排序
distinct().values(‘field_name’) 去点掉重复的
[n:m] 起始与偏移量，[0:10] 取出1~10

常用查询方法：
这里写图片描述

修改数据库值：
修改 id = 1 的信息

from django.http import HttpResponsefrom django.template import loader,Contextfrom blog.models import Person# Create your views here.def student_list(request):    t = loader.get_template('student.html')    newrow = Person(name = 'LiMing',age = 18,initime = '2016-02-02')    newrow.save() # 等同于 insert 插入一行    student = Person.objects.get(id = 2)    student.delete() #删除 id = 2 的    #Person.objects.all().delete()  #删除所有    studentList = Person.objects. filter(age_lt = 30).update(name = 'xyz') #把年龄小于30 岁的人的name改为 xyz      student = Person.objects.get(id = 1)   #获得的是单个数据 不是数组    student.name = 'Tom'    student.age = '29'    student.save()              #保存    c = Context({ 'student':student })    return HttpResponse(t.render(c))--------------------------------------------------------------------------studentList = Person.objects. filter(age_lt = 30).update(name = 'xyz') 相当于：update Person set name = 'xyz' where age < 30

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