1.一对多跨表查询获取数据的三种形式:对象、字典、元组
例:有host与business两张表,host与business的id字段关联,business在host表中的对象名是b, 通过查询host表获取的querySet中的b来查询business表。
以下两种方式都是操作host表:
a.以对象的形式跨表查询,查询business表的数据:row.b.caption,row.b.id
b.以字典和元组的形式跨表查询,查询business表的数据,跨表查询的时候要用双下划线 'b__id','b__caption', # 这里caption是关联表business的字段
views.py


def host(request):#三种形式的跨表查询(这里有host与business两张表,host与business的id字段关联,business在host表中的对象名是b,# 通过查询host表获取的querySet来查询business表)v1 = models.Host.objects.filter(nid__gt=0)for row in v1:#v1以对象的形式跨表查询row.b.caption, ,row.b.idprint(row.nid,row.hostname,row.ip,row.port,row.b.caption,row.b.id)v2 = models.Host.objects.all().values('nid','hostname','b_id','b__caption',)for row2 in v2:# v2以字典的形式跨表查询,跨表查询(即查询另一个关联表的数据)的时候要用双下划线'b__caption',这里caption是关联表的字段print(row2) #结果是字典 {'nid': 8, 'hostname': 'ee', 'b_id': 5, 'b__caption': '运维'}print(row2['nid'],row2['hostname'],row2['b_id'],row2['b__caption'])v3 = models.Host.objects.all().values_list('nid','hostname','b_id','b__caption')for row3 in v3:# v3以元组的形式跨表查询,跨表查询(即查询另一个关联表的数据)的时候要用双下划线'b__caption',这里caption是关联表的字段print(row3)#结果是元组 (7, 'wt', 6, '开发')print(row3[0],row3[1],row3[2],row3[3])if request.method == 'GET':v1 = models.Host.objects.filter(nid__gt=0)v2 = models.Host.objects.all().values('nid', 'hostname', 'b_id', 'b__caption', )v3 = models.Host.objects.all().values_list('nid', 'hostname', 'b_id', 'b__caption')b_list = models.Business.objects.all()return render(request, 'host.html', {'v1':v1, 'v2':v2, 'v3':v3,'b_list':b_list})elif request.method == 'POST':h = request.POST.get('hostname')i = request.POST.get('ip')p = request.POST.get('port')b = request.POST.get('b_id')models.Host.objects.create(hostname=h,ip=i,port=p,b_id=b,)return redirect('/host')
host.html


<!DOCTYPE html> <html lang="en"> <head><meta charset="UTF-8"><title>Title</title> </head> <body><h1>对象</h1><table border="1" style="border-collapse: collapse;"><thead><tr><th>主机名</th><th>IP</th><th>端口</th><th>业务线名称</th></tr></thead><tbody>{% for row in v1 %}<tr hid="{{ row.nid }}" bid="{{ row.b_id }}"><td>{{ row.hostname }}</td><td>{{ row.ip }}</td><td>{{ row.port }}</td> {# 查关联表的其他字段caption,这里b是关联表的对象名#}<td>{{ row.b.caption }}</td></tr>{% endfor %}</tbody></table><h1>字典</h1><table border="1" style="border-collapse: collapse;"><thead><tr><th>主机名</th><th>业务线名称</th></tr></thead><tbody>{% for row in v2 %}<tr hid="{{ row.nid }}" bid="{{ row.b_id }}"><td>{{ row.hostname }}</td> {# 查关联表的其他字段caption,这里b是关联表的对象名#}<td>{{ row.b__caption }}</td></tr>{% endfor %}</tbody></table><h1>元组</h1><table border="1" style="border-collapse: collapse;"><thead><tr><th>主机名</th><th>业务线名称</th></tr></thead><tbody>{% for row in v3 %}<tr hid="{{ row.0 }}" bid="{{ row.2 }}"><td>{{ row.1 }}</td><td>{{ row.3 }}</td>{# 查关联表的其他字段caption,这里b是关联表的对象名#}<td>{{ row.b.caption }}</td></tr>{% endfor %}</tbody></table> </body> </html>
2.模板语言显示序号用forloop,只有for循环里有。
1 <tbody> 2 {% for row in v1 %} 3 <tr hid="{{ row.nid }}" bid="{{ row.b_id }}"> 4 <td>{{ forloop.counter }}</td> 5 {#在for循环里才有forloop,forloop.counter自动加序号,从1开始#} 6 {#forloop.counter0自动加序号,从0开始#} 7 {#forloop.revcounter自动加序号,倒数#} 8 <td>{{ row.hostname }}</td> 9 <td>{{ row.ip }}</td> 10 <td>{{ row.port }}</td> 11 <td>{{ row.b.caption }}</td> 12 </tr> 13 {% endfor %} 14 </tbody>
3.后端接收前端多选框、Ctrl多选的数据用method.getlist()
views.py
1 elif request.method == "POST": 2 app_name = request.POST.get('app_name') 3 host_list = request.POST.getlist('host_list')#当前端是多选传过来的数据时,用getlist接收,生成列表 4 print(app_name,host_list) 5 6 obj = models.Application.objects.create(name=app_name) 7 obj.r.add(*host_list) #多对多跨表添加数据:*列表名 8 9 return redirect('/app')
html多选
1 <div class="group"> 2 <select id="host_list" name="host_list" multiple> 3 #multiple是多选的意思 4 {% for op in host_list %} 5 <option value="{{ op.nid }}">{{ op.hostname }}</option> 6 {% endfor %} 7 </select> 8 </div>
4.编辑框的实现和ajax提交表单数据
d20-host.html
{# 下边是编辑框展示#}<div class="shade hide"></div><div class="add-modal hide"><form id="add_form" method="POST" action="/host"><div class="group"><input id="host" type="text" placeholder="主机名" name="hostname" /></div><div class="group"><input id="ip" type="text" placeholder="IP" name="ip" /></div><div class="group"><input id="port" type="text" placeholder="端口" name="port" /></div><div class="group"><select id="sel" name="b_id">{% for op in b_list %} {# 生成下拉框#}<option value="{{ op.id }}">{{ op.caption }}</option>{% endfor %}</select></div><input type="submit" value="提交" /><a id="ajax_submit" >悄悄提交</a><input id="cancel" type="button" value="取消" /><span id="erro_msg" style="color: red"></span>提交失败,错误信息显示</form>$('#ajax_submit').click(function(){$.ajax({url: "/test_ajax",type: 'POST',//data: {'hostname': $('#host').val(), 'ip': $('#ip').val(), 'port': $('#port').val(), 'b_id': $('#sel').val()},data: $('#add_form').serialize(), //serialize()是ajax方法,它能自动找到表单中的name和value数据并提交给后台,跟上边的效果相同 success: function(data){var obj = JSON.parse(data);if(obj.status){location.reload();//提交成功自动刷新页面}else{$('#erro_msg').text(obj.error);//提交失败显示错误信息}}})});
views.py
后台数据接收
1 elif request.method == "POST": 2 3 h = request.POST.get('hostname') 4 i = request.POST.get('ip') 5 p = request.POST.get('port') 6 b = request.POST.get('b_id') 7 models.Host.objects.create(hostname=h, 8 ip=i, 9 port=p, 10 b_id=b, 11 ) 12 return redirect('/host')
5.初识ajax,ajax发送普通数据与发送列表
重要:在html中写ajax
ajax操作要点: 1. <form id='ajax_text'action='/yy.html' method='post'> #id='ajax_text'方便ajax获取数据;action='/yy.html'点击取消后 跳转到的页面;2. <input id="ajax_submit" type="button" value="提交" /> #id="ajax_submit" :方便ajax进行绑定</form> 3. <span id="error_msg" style="color: white"></span> #显示提示信息4. $('#ajax_submit').click(function(){$.ajax({url: "/test_ajax",type: 'POST',dataType:'JSON', #自动转换json数据 traditional:true,data: $('#add_form').serialize(),//ajax用serialize()提交表单数据,serialize()能自动获取表单中的name和value并提交给后台success: function(data){if(data.status){location.reload(); //自动刷新页面}else{$('#error_msg').text(data.error); //在模态对话框里显示错误信息}}})});
ajax格式:
1 Ajax格式:在html的script中
A.发送数据格式为普通数据data: {'k1': 123,'k2': "root"}, 2 3 $.ajax({ 4 url: '/host', //数据提交的url 5 type: "POST", //数据提交方式,除了post还有get 6 data: {'k1': 123,'k2': "root"}, //要给后端发送提交的数据,data只能是字典
dataType:'JSON', //写上这句,就不用再在下边做字符串与字典转换了,ajax内部自动转换 7 success: function(data){ //success里写函数 8 // data是服务器端返回的字符串 9 var obj = JSON.parse(data); //有了上边的dataType:'JSON',这里就不用做字符串转换成字典了 10 } 11 }) 12 B.发送数据格式为列表:data: {'user': 123,'host_list': [1,2,3,4]},
$.ajax({
url: '/ajax_add_app',
data: {'user': 123,'host_list': [1,2,3,4]},或
data: $('#add_form').serialize(), //这里serialize()会找到id=add_form的表单,(这里id必须为表单<form>的id)并且自动获取form表单中的name和value,
因此不用再写成data: {'user': 123,'host_list': [1,2,3,4]}这样了
type: "POST",
dataType: 'JSON',// 内部 自动将字符串转换为字典
traditional: true, //要发送列表必须要加traditional: true参数,否则发送为空
success: function(obj){ //请求成功,要发送的数据
console.log(obj);
},
error: function () { //请求失败,要发送的数据
}
})
13 14 建议:永远让服务器端返回一个字典 15 16 return HttpResponse(json.dumps(字典))
后端views.py,后端一定要永远给前端返回一个字典,而且return一定要返回HttpResponse
1 def test_ajax(request): 2 ret = {'status': True, 'error': None, 'data': None} #初始化一个字典 3 try: #获取ajax请求 4 h = request.POST.get('hostname') 5 i = request.POST.get('ip') 6 p = request.POST.get('port') 7 b = request.POST.get('b_id') 8 if h and len(h) > 5: #判断用户名的长度是否大于5,如果小于5则返回error值 9 models.Host.objects.create(hostname=h, 10 ip=i, 11 port=p, 12 b_id=b) 13 else: 14 ret['status'] = False 15 ret['error'] = "太短了" 16 except Exception as e: 17 ret['status'] = False 18 ret['error'] = '请求错误' 19 return HttpResponse(json.dumps(ret)) #这里只能用HttpResponse,而且HttpResponse里边只能写字符串,所以往前端传输字典的时候要将字典序列化成字符串
前端html,在js里,通过var obj = JSON.parse(data); 将后端发过来的字符串转换为字典


1 <div class="add-modal hide"> 2 <form id="add_form" method="POST" action="/host"> 3 <div class="group"> 4 <input id="host" type="text" placeholder="主机名" name="hostname" /> 5 </div> 6 <div class="group"> 7 <input id="ip" type="text" placeholder="IP" name="ip" /> 8 </div> 9 10 <div class="group"> 11 <input id="port" type="text" placeholder="端口" name="port" /> 12 </div> 13 14 <div class="group"> 15 <select id="sel" name="b_id"> 16 {% for op in b_list %} 17 <option value="{{ op.id }}">{{ op.caption }}</option> 18 {% endfor %} 19 </select> 20 </div> 21 22 <input type="submit" value="提交" /> 23 <a id="ajax_submit" >悄悄提交</a> 24 <input id="cancel" type="button" value="取消" /> 25 <span id="erro_msg" style="color: red"></span> 26 {# span显示错误信息#} 27 </form> 28 29 <script> 30 $('#ajax_submit').click(function(){ 31 $.ajax({ 32 url: "/test_ajax", 33 type: 'POST', 34 //data: {'hostname': $('#host').val(), 'ip': $('#ip').val(), 'port': $('#port').val(), 'b_id': $('#sel').val()}, 35 data: $('#add_form').serialize(),//ajax用serialize()提交表单数据,serialize()能自动获取表单中的name和value并提交给后台,效果跟上边这句一样 36 success: function(data){ 37 var obj = JSON.parse(data); //js将字符串转换为字典 38 var dd = JSON.stringify(obj) //js将字典转换为字符串 39 if(obj.status){ 40 location.reload(); //自动刷新页面 41 }else{ 42 $('#erro_msg').text(obj.error); //在模态对话框里显示错误信息 43 } 44 } 45 }) 46 }); 47 </script>
6.多对多创建关系表 有2种方式
方式一:自定义关系表。推荐用这种方式创建
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')# 10class Application(models.Model):name = models.CharField(max_length=32)# 2class HostToApp(models.Model):#生成hosttoapp关联表,该表有三列,分别是id、hobj_nid、aobj_id,还可以自定义增加其他列名hobj = models.ForeignKey(to='Host',to_field='nid')aobj = models.ForeignKey(to='Application',to_field='id')
在往方式一创建的关系表hosttoapp表中插入数据的时候,直接用普通的orm语句即可:
HostToApp.objects.create(hobj_id=1,aobj_id=2)
方式二:自动创建关系表。这种方式通过两个类可以创建三张表
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')# 10class Application(models.Model):name = models.CharField(max_length=32)r = models.ManyToManyField("Host") #这里用ManyToManyField关键字,可以自动创建第三张表----即host与application表之间的关联表,表名是:app01_application_r;
其中app01是项目名,该表中含有三列,分别是:id、application_id、host_id,但该表不能自定义增加其他列
通过方式二创建的关系表app01_application_r表,是无法直接向该表插入数据的。要操作数据必须用以下方式:
obj = Application.objects.get(id=1) #获取application表application_id=1所有数据的对象
查obj.name #获取application_id=1对应所有数据的应用名# 第三张表(关系表)操作
增
添加数据操作,有三种方式:1、obj.r.add(1) 添加数据。这里的1是另一列host_id的数值,即在application表中添加application_id=1,host_id=1obj.r.add(2)2、obj.r.add(2,3,4) 添加数据。这里的2,3,4是另一列host_id的数值,即在application表中添加application_id=1,host_id=2;application_id=1,host_id=3;
application_id=1,host_id=4的数值3、obj.r.add(*[1,2,3,4]) 添加数据。这里的1,2,3,4是另一列host_id 的数值,即在application表中添加application_id=1,host_id=1;application_id=1,host_id=2;
application_id=1,host_id=3;application_id=1,host_id=4的数值
删 obj.r.remove(1) 删除数据obj.r.remove(2,4)obj.r.remove(*[1,2,3])obj.r.clear() 清除数据。清除application表中application_id=1所对应的所有host_id的值改obj.r.set([3,5,7]) 修改数据。列表不加*,将application_r表中application_id=1所对应的所有host_id的值修改为3,5,7,即表中application_id=1所对应的所有host_id的值只剩下3,5,7# 通过关系表app01_application_r查询host表
obj = Application.objects.get(id=1)ss = obj.r.all() 这里ss是querySet,这个querySet里存放的是application_id=1包括的所有host_id对应host表的一行行数据对象,也就是说ss就是host表中相应host_id所在行的数据对象集合,
要获取每个host行对象的详细信息,要用for循环
for h in ss:
print(h.hostname,h.id,h.port)
7.多对多增加、编辑示例,用ajax,详见d20-12
views.py


from django.shortcuts import render,HttpResponse,redirect from app01 import models import json # Create your views here.def business(request):v1 = models.Business.objects.all()# QuerySet# [obj(id,caption,code),obj(id,caption,code),obj(id,caption,code) ] v2 = models.Business.objects.all().values('id','caption')# QuerySet# [{'id':1,'caption': '��ά��'},{'id':1,'caption': '��ά��'},...] v3 = models.Business.objects.all().values_list('id','caption')# QuerySet# [(1����ά��),(2,����)]return render(request, 'business.html', {'v1': v1,'v2': v2, 'v3': v3})# def host(request): # v1 = models.Host.objects.filter(nid__gt=0) # # QuerySet [hostobj(ip.host,����һ������(..)),] # # for row in v1: # # print(row.nid,row.hostname,row.ip,row.port,row.b_id,row.b.caption,row.b.code,row.b.id,sep='\t') # # print(row.b.fk.name) # # return HttpResponse("Host") # v2 = models.Host.objects.filter(nid__gt=0).values('nid','hostname','b_id','b__caption') # # QuerySet: [ {} ] # # print(v2) # # for row in v2: # # print(row['nid'],row['hostname'],row['b_id'],row['b__caption']) # # v3 = models.Host.objects.filter(nid__gt=0).values_list('nid','hostname','b_id','b__caption') # # QuerySet: [ {} ] # # print(v2) # return render(request, 'host.html', {'v1': v1,'v2': v2,'v3': v3})def host(request):if request.method == "GET":v1 = models.Host.objects.filter(nid__gt=0)v2 = models.Host.objects.filter(nid__gt=0).values('nid','hostname','b_id','b__caption')v3 = models.Host.objects.filter(nid__gt=0).values_list('nid','hostname','b_id','b__caption')b_list = models.Business.objects.all()return render(request, 'host.html', {'v1': v1,'v2': v2,'v3': v3,'b_list':b_list})elif request.method == "POST":h = request.POST.get('hostname')i = request.POST.get('ip')p = request.POST.get('port')b = request.POST.get('b_id')# models.Host.objects.create(hostname=h,# ip=i,# port=p,# b=models.Business.objects.get(id=b)# )models.Host.objects.create(hostname=h,ip=i,port=p,b_id=b)return redirect('/host')def test_ajax(request):ret = {'status': True, 'error': None, 'data': None} #初始化一个字典try: #获取ajax请求h = request.POST.get('hostname')i = request.POST.get('ip')p = request.POST.get('port')b = request.POST.get('b_id')if h and len(h) > 5: #判断用户名的长度是否大于5,如果小于5则返回error值models.Host.objects.create(hostname=h,ip=i,port=p,b_id=b)else:ret['status'] = Falseret['error'] = "太短了"except Exception as e:ret['status'] = Falseret['error'] = '请求错误'return HttpResponse(json.dumps(ret)) #HttpResponse里边只能写字符串,所以往前端传输字典的时候要将字典序列化成字符串def app(request):if request.method == "GET":app_list = models.Application.objects.all()# for row in app_list:# print(row.name,row.r.all()) host_list = models.Host.objects.all() #从host表取host数据,来生成host列表下拉框return render(request,'app.html',{"app_list": app_list,'host_list': host_list})elif request.method == "POST":app_name = request.POST.get('app_name')host_list = request.POST.getlist('host_list')# 后端获取列表数据用getlistprint(app_name,host_list)obj = models.Application.objects.create(name=app_name)obj.r.add(*host_list) #往关系表中添加数据,这里的host_list是列表,所以要加*号return redirect('/app')def ajax_add_app(request):ret = {'status':True, 'error':None, 'data': None}app_name = request.POST.get('app_name')host_list = request.POST.getlist('host_list')obj = models.Application.objects.create(name=app_name)obj.r.add(*host_list)return HttpResponse(json.dumps(ret))
app.html


<!DOCTYPE html> <html lang="en"> <head><meta charset="UTF-8"><title></title><style>.host-tag{display: inline-block;padding: 3px;border: 1px solid red;background-color: palevioletred;}.hide{display: none;}.shade{position: fixed;top: 0;right: 0;left: 0;bottom: 0;background: black;opacity: 0.6;z-index: 100;}.add-modal,.edit-modal{position: fixed;height: 300px;width: 400px;top:100px;left: 50%;z-index: 101;border: 1px solid red;background: white;margin-left: -200px;}</style> </head> <body><h1>应用列表</h1><div><input id="add_app" type="button" value="添加" /></div><table border="1"><thead><tr><td>应用名称</td><td>应用主机列表</td></tr></thead><tbody>{% for app in app_list %}<tr aid="{{ app.id }}"><td>{{ app.name }}</td><td>{% for host in app.r.all %}<span class="host-tag" hid="{{ host.nid }}"> {{ host.hostname }} </span>{% endfor %}</td><td><a class="edit">编辑</a></td></tr>{% endfor %}</tbody></table><div class="shade hide"></div><div class="add-modal hide"><form id="add_form" method="POST" action="/app"><div class="group"><input id="app_name" type="text" placeholder="应用名称" name="app_name" /></div><div class="group"><select id="host_list" name="host_list" multiple>multiple是按住Ctrl多选,这里做一个下拉框,来进行多选选择{% for op in host_list %}<option value="{{ op.nid }}">{{ op.hostname }}</option>这里的op.nid就是每个hostname对应的id,提交的时候,就会将这些选中的op.nid以列表的形式提交给后端{% endfor %}</select></div><input type="submit" value="提交" /><input id="add_submit_ajax" type="button" value="Ajax提交" /></form></div><div class="edit-modal hide"><form id="edit_form" method="POST" action="/host"><input type="text" name="nid" style="display:none" /><input type="text" placeholder="应用名称" name="app" /><select name="host_list" multiple>multiple是按住Ctrl多选,这里做一个下拉框,来进行多选选择{% for op in host_list %}<option value="{{ op.nid }}">{{ op.hostname }}</option>{% endfor %}</select><a id="ajax_submit_edit" >确认编辑</a></form></div><script src="/static/jquery-1.12.4.js"></script><script>$(function(){$('#add_app').click(function(){$('.shade,.add-modal').removeClass('hide');});$('#cancel').click(function(){$('.shade,.add-modal').addClass('hide');});$('#add_submit_ajax').click(function(){$.ajax({url: '/ajax_add_app',// data: {'user': 123,'host_list': [1,2,3,4]}, data: $('#add_form').serialize(),type: "POST",dataType: 'JSON', // 内部 traditional: true,success: function(obj){console.log(obj);},error: function () {}})});$('.edit').click(function(){$('.edit-modal,.shade').removeClass('hide');var hid_list = [];$(this).parent().prev().children().each(function(){var hid = $(this).attr('hid');hid_list.push(hid)});$('#edit_form').find('select').val(hid_list);// 如果发送到后台// /*obj = models.Application.objects.get(id=ai)obj.name = "新Name"obj.save()obj.r.set([1,2,3,4])*/})})</script> </body> </html>