Django框架学习笔记（17.多对多简易实例）

来源：互联网发布：法比奥奥奥知乎编辑：程序博客网时间：2024/05/29 09:05

创建多对多：

方式一（自定义关系表）

class Host(models.Model):    nid = models.AutoField(primary_key=True)    hostname = models.CharField(max_length=32, db_index=True)    ip = models.GenericIPAddressField(db_index=True)    port = models.IntegerField()    b = models.ForeignKey(to="Business", to_field='id', on_delete=models.CASCADE)class Application(models.Model):    name = models.CharField(max_length=32)class HostToApp(models.Model):    hobj = models.ForeignKey(to='Host', to_field='nid', on_delete=models.CASCADE)    aobj = models.ForeignKey(to='Application', to_field='id', on_delete=models.CASCADE)操作：models.HostToApp.objects.create(hobj_id=1,aobj_id=2)

方式二（自动创建关系表）（缺点是不能创建多个表的多对多）

class Host(models.Model):    nid = models.AutoField(primary_key=True)    hostname = models.CharField(max_length=32, db_index=True)    ip = models.GenericIPAddressField(db_index=True)    port = models.IntegerField()    b = models.ForeignKey(to="Business", to_field='id', on_delete=models.CASCADE)class Application(models.Model):    name = models.CharField(max_length=32)    r = models.ManyToManyField("Host") #自动创建了一个app01_application_r表#无法直接对第三张表操作，可以间接操作obj = Application.objects.get(id=1)obj.r.add(1)#在第三张表里面增加一个1对应1obj.r.remove(1)obj.r.clear()    #清除id=1的全部obj.r.set()      #更改

接下来在以前的基础上写一个简单的（采用上面的方式二）：

views.py部分(加入相应url对应关系)：

def app(request):    if request.method == "GET":        app_list = models.Application.objects.all()        host_list = models.Host.objects.all()        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')        print(app_name, host_list)        obj = models.Application.objects.create(name=app_name)        obj.r.add(*host_list)        return redirect('/app')import jsondef 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</title>    <style>        .host-tag{            display: inline-block;            padding: 3px;            border: 1px solid red;            background-color: chartreuse;        }        .hide {            display: none;        }        .shade {            position: fixed;            top: 0;            right: 0;            bottom: 0;            left: 0;            background-color: black;            opacity: 0.6;            z-index: 100;        }        .add-model, .edit-model {            position: fixed;            height: 300px;            width: 400px;            top: 100px;            left: 50%;            z-index: 101;            border: 1px solid red;            background-color: 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</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-model hide">    <form id="add_form" method="POST" action="/app">        <div class="group">            <input id="app_name" type="text" placeholder="应用名" name="app_name"/>        </div>        <div>            <select name="host_list" multiple>                {% for op in host_list %}                    <option value="{{ op.nid }}">{{ op.hostname }}</option>                {% 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-model 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>                {% 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></table><script src="/static/jquery1.js"></script><script>    $(function () {        $('#add_app').click(function () {            $('.shade,.add-model').removeClass('hide')        });        $('#cancel').click(function () {            $('.shade,.add-model').addClass('hide')        });        $('#add_submit_ajax').click(function () {            $.ajax({                url: 'ajax_add_app',                data: $('#add_form').serialize(),                type: "POST",                dataType:"JSON",                traditional: true,                success:function(obj){                    //这里写入相关操作                },                error:function(){                }            })        });        $('.edit').click(function(){            $('.edit-model,.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);            /*obj = models.Application.objects.get(id = aid)            obj.name = "new name"            obj.save()            obj.r.set([1,2,3,4])*/        });    })</script></body></html>

阅读全文

0 0