1、models.py中创建类和字段
from django.db import models # Create your models here. class Business(models.Model): caption = models.CharField(max_length=32) code = models.CharField(max_length=32,default='SA')#default='SA' 默认是SA class Host(models.Model): nid = models.AutoField(primary_key=True) hostname = models.CharField(max_length=32,db_index=True) ip = models. GenericIPAddressField(protocol='ipv4',db_index=True) port = models.IntegerField() b = models.ForeignKey(to='Business',to_field='id')
外键关联的时候如果没写和另一个表的哪个字段关联的话，默认是和主键关联。
2、python manage.py makemigrations
python manage.py migrate
settings.py 需要注册APP
如果表中已经存在数据，新增字段的时候加上default='SA'或者null=True
views.py
from django.shortcuts import render from app01 import models # Create your views here. def business(request): v1 = models.Business.objects.all() #QuerySet v2 = models.Business.objects.all().values('id','caption') v3 = models.Business.objects.all().values_list('id','caption') return render(request,'business.html',{'v1':v1,'v2':v2,'v3':v3}) def host(request): v = models.Host.objects.filter(nid__gt=0) print(v) return render(request,'host.html',{'v':v})
单表查询的三种方式
- # QuerySet ,内部元素都是对象
v1 = models.Business.objects.all()
- # QuerySet ,内部元素都是字典
v2 = models.Business.objects.all().values('id','caption')
- # QuerySet ,内部元素都是元组
v3 = models.Business.objects.all().values_list('id','caption')
获取到的一个对象，如果不存在就报错
models.Business.objects.get(id=1)
对象或者None = models.Business.objects.filter(id=1).first()、
一对多跨表操作
def host(request): if request.method == 'GET': v = models.Host.objects.filter(nid__gt=0) v1 = models.Host.objects.filter(nid__gt=0).values('hostname','ip','port','b_id','b__caption') v2 = models.Host.objects.filter(nid__gt=0).values_list('hostname','ip','port','b_id','b__caption')#跨表时用__ b = models.Business.objects.all() print(b) return render(request,'host.html',{'v':v,'v1':v1,'v2':v2,'b':b}) elif request.method == 'POST': h = request.POST.get('hostname') ip = request.POST.get('ip') p = request.POST.get('port') b = request.POST.get('b') models.Host.objects.create(hostname=h,ip=ip,port=p,b_id=b) return redirect('/host')
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <table border="1"> <thead> <tr> <th>主机名</th> <th>ip</th> <th>端口</th> <th>业务线</th> <th>编号</th> </tr> </thead> <tbody> {% for row in v %} <tr nid="{{ row.nid }} " pid="{{ row.b_id }}"> <td>{{ row.hostname }}</td> <td>{{ row.ip }}</td> <td>{{ row.port }}</td> <td>{{ row.b_id }}</td> <td>{{ row.b.caption }}</td> </tr> {% endfor %} </tbody> </table> </body> </html>
PS：在host表中，外键关联business表，在创建完host表的时候，会出现b_id字段，就是business的id。但是也能通过b这个字段来查询business表的属性，此时row.b就是business对象，business表的一行数据,row.b.caption就能查询到business的字段。
在business表中，host_set能反查
from django.db import models # Create your models here. class UserType(models.Model): name = models.CharField(max_length=32,unique=True) class User(models.Model): name = models.CharField(max_length=64) pwd = models.CharField(max_length=64) type = models.ForeignKey(to='UserType',to_field='id',related_name='b')
正向查询
v= models.User.objects.all()
方式一：
for item in v:
item.name
item.pwd
item.type.name
方式二：
models.User.objects.all().values('name','type__name')
反向查询
v = models.UserType.objects.all()
方式一：
for item in v:
item.name
item.id
item.user_set.all() --item.b.all()
方式二：
models.UserType.objects.all().values('name','user__pwd')
ajax
$(function () {
$('#ajax_add').click(function () {
$.ajax({
url:'/test_ajax/',
type:'POST',
data:{'h':$('#host').val(),'ip':$('#ip').val(),'port':$('#port').val()},
success:function (data) {#data是服务器端返回的字符串
if(data=='ok'){
location.reload()
}else{
alert(data);
}
}
})
})
})
如果发送的是一个列表，加上traditional=True
success后面的函数function只有在post数据后得到返回值才会执行
让服务器端返回一个字典
return HttpResponse
views.py
def test_ajax(requset): import json ret = {'status':True,'error':None,'data':None} try: h = requset.POST.get('h') ip = requset.POST.get('ip') port = requset.POST.get('port') b_id = requset.POST.get('b_id') if h and len(h) > 5: models.Host.objects.create(hostname=h,ip=ip,port=port,b_id=b_id) else: ret['status'] = False ret['error'] = '太短了' except Exception as e: ret['status'] = False ret['error'] = '请求错误' return HttpResponse(json.dumps(ret))
host.html
$.ajax({
url:'/test_ajax/',
type:'POST',
data:{'h':$('#host').val(),'ip':$('#ip').val(),'port':$('#port').val(),'b_id':$('#b_id').val()},
success:function (data) {
var obj = JSON.parse(data);
if (obj.status){
location.reload();
}else {
$('#msg').text(obj.error);
}
console.log(data)
}
})
})
js中字符串-》字典 JSON.parse
页面重新加载 location.reload()
多对多
方式一：自定义创建
class Host(models.Model):
nid = models.AutoField(primary_key=True)
hostname = models.CharField(max_length=32,db_index=True)
ip = models. GenericIPAddressField(protocol='ipv4',db_index=True)
port = models.IntegerField()
b = models.ForeignKey(to='Business',to_field='id')
class Application(models.Model):
name = models.CharField(max_length=32)
class HostToApplication(models.Model):
hobj = models.ForeignKey('Host',to_field='nid')
aobj = models.ForeignKey('Application',to_field='id')
方式二：django自动创建第三张表，只能有3列
class Host(models.Model):
nid = models.AutoField(primary_key=True)
hostname = models.CharField(max_length=32,db_index=True)
ip = models. GenericIPAddressField(protocol='ipv4',db_index=True)
port = models.IntegerField()
b = models.ForeignKey(to='Business',to_field='id')
class Application(models.Model):
name = models.CharField(max_length=32)
r = models.ManyToManyField('Host')
正向增加：通过app加主机
app_obj = models.Application.objects.get(id=1)
host_obj = models.Host.objects.all()
app_obj.r.add(*host_obj)
host_obj.r.add(*[1,2,3])
正向查找：通过app查主机
app_obj = models.Application.objects.get(id=1)
for host in app_obj.r.all():
host.ip
反向增加：通过主机加app 主机table中有隐藏字段application_set
host_obj = models.Host.objects.get(ip='1.1.1.1')
application_obj = models.Application.objects.filter(id__lt=2)
host_obj.application_set.add(*application_obj)
反向查询：
host_obj = models.Host.objects.get(ip='1.1.1.1')
app_obj = host_obj.application_set.all()
for app in app_obj:
print(app.name)
obj.remove(*[1,2,3])
obj.r.clear()
obj.r.set([3,5,7])
所有相关的主机对象‘列表’
obj.r.all()
*外键用select_related()
*多对多 prefetch_related()
更多 多对多操作请看
http://www.mamicode.com/info-detail-1292278.html