Django 之组合搜索

现在很多网站都会有这样的组合搜索功能，其实质是几个模型之间组合对数据库进行查询，并将结果显示到页面上。

每一行都是一个模型，模型之间有着连表关系（一对多、多对多等）

模型设计

• 总共四个模型：分别为方向、分类、等级以及存储结果信息
• 一个方向下可以有多个分类，一个分类也可以是多个方向（多对多）
• 一个分类可以有多个视频（一对多）
• 一个等级下也可以有多个视频（一对多）

from django.db import models


class Direction(models.Model):
    """方向：自动化、测试、运维、前端"""
    name = models.CharField(verbose_name='名称', max_length=32)
    classification = models.ManyToManyField('Classification')

    class Meta:
        db_table = 'Direction'
        verbose_name_plural = '方向（视频方向）'        # 模型的复数形式，若不指定则在后面加一个 s

    def __str__(self):
        return self.name


class Classification(models.Model):
    """分类：Python、Linux、JavaScript、OpenStack、Node.js、C"""
    name = models.CharField(verbose_name='名称', max_length=32)

    class Meta:
        db_table = 'Classification'
        verbose_name_plural = '分类（视频分类）'

    def __str__(self):
        return self.name


class Level(models.Model):
    """等级：初级、中级、高级、骨灰级"""
    title = models.CharField(max_length=32)

    class Meta:
        verbose_name_plural = '难度级别'

    def __str__(self):
        return self.title


class Video(models.Model):
    status_choice = (
        (1, '下线'),
        (2, '上线'),
    )

    status = models.IntegerField(verbose_name='状态', choices=status_choice, default=1)
    level = models.ForeignKey('Level', on_delete=models.CASCADE)
    classification = models.ForeignKey('Classification', null=True, blank=True, on_delete=models.CASCADE)

    weight = models.IntegerField(verbose_name='权重（从大到小排列）', default=0)

    title = models.CharField(verbose_name='标题', max_length=32)
    summary = models.CharField(verbose_name='简介', max_length=100)

    # 也可以用 ImgField 或 FileField 存储图片，而不是 CharField，但是要指定存储路径
    # img = models.ImgField(verbose_name='图片', upload_to='app/static/app/video')
    img = models.CharField(verbose_name='图片', max_length=200)
    href = models.CharField(verbose_name='视频地址', max_length=256)

    create_data = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = 'Video'
        verbose_name_plural = '视频'

    def __str__(self):
        return self.title

URlconf 配置

urlconf 配置采用的是二级路由，即应用本身创建 urls.py：

# project/urls.py
from django.contrib import admin
from django.urls import path, include

urlpatterns = [
    path('admin/', admin.site.urls),
    path('app/', include('app.urls')),
]

# app/urls.py
from django.urls import path
from app import views

urlpatterns = [
    path('video/<int:classification_id>/<int:level_id>/<int:status>/', views.video, name='video'),
    path('video2/<int:direction_id>/<int:classification_id>/<int:level_id>/', views.video2, name='video2'),
]

一对多

一对多关系中主要是视频信息与分类、等级之间的关系操作。

视图函数

函数接收三个额外参数，分别为：分类 classification id、等级 level id 以及状态 status id。根据这三个参数构造查询条件（filter() 函数本身是支持字典形式查询的）。

Tips

condition 构造的查询条件是字典形式，其键 key应与数据表中相应字段对应，如： classification_id 为模型 Video与 Classification 的外键字段名。

from django.shortcuts import render, HttpResponse
from app.models import Level, Classification, Direction, Video


def video(request, *args, **kwargs):
    print(args, kwargs)     # () {'classification_id': 1, 'level_id': 2}

# 构造查询条件
    condition = {
        # 'classification_id': 0,
        # 'level_id': 0
    }

    # 当 kwargs = {'classification_id': 0, 'level_id': 0} 时，condition = {}，
    # Video.objects.filter(**condition) 能把所有的都查出来
    # 当 kwargs = {'classification_id': 1, 'level_id': 1} 时，condition = {'classification_id': 1, 'level_id': 1}
    # filter() 支持字典格式
    # 将其转换为整数
    for k, v in kwargs.items():
        temp = int(v)
        kwargs[k] = temp
        if temp:
            condition[k] = temp

    class_list = Classification.objects.all()
    level_list = Level.objects.all()

    # 查询数据
    video_list = Video.objects.filter(**condition)

    """
       status_choice = (
           (1, '下线'),
           (2, '上线'),
       )
       """
    # status_list：[{'id': 1, 'name': '下线'}, {'id': 2, 'name': '上线'}]
    status_list = list(map(lambda x: {'id': x[0], 'name': x[1]}, Video.status_choice))

    return render(
        request,
        'app/video.html',
        {
            'kwargs': kwargs,
            'class_list': class_list,
            'level_list': level_list,
            'video_list': video_list,
            'status_list': status_list
        }
    )

模板

{% load static %}
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>视频</title>
    <style type="text/css">
        .box1 a{
            display: inline-block;
            padding: 5px 8px;
            border: 1px solid #dddddd;
        }

        .box1 a.active{
            background-color: coral;
            color: white;
        }

    </style>
</head>
<body>
    <div class="box1">
        <h1>筛选</h1>
        <!--分类-->
        <div>
            {% if kwargs.classification_id == 0 %}
                <a class="active" href="/app/video/0/{{ kwargs.level_id }}/{{ kwargs.status }}">全部</a>
            {% else %}
                <a href="/app/video/0/{{ kwargs.level_id }}/{{ kwargs.status }}">全部</a>
            {% endif %}

            {% for class in class_list %}
                {% if class.id == kwargs.classification_id %}
                    <a href="/app/video/{{ class.id }}/{{ kwargs.level_id }}/{{ kwargs.status }}" class="active">{{ class.name }}</a>

                {% else %}
                    <a href="/app/video/{{ class.id }}/{{ kwargs.level_id }}/{{ kwargs.status }}">{{ class.name }}</a>
                {% endif %}

            {% endfor %}

        </div>


        <!--等级-->
        <div>
            {% if kwargs.level_id == 0 %}
                <a href="/app/video/{{ kwargs.classification_id }}/0/{{ kwargs.status }}" class="active">全部</a>
            {% else %}
                <a href="/app/video/{{ kwargs.classification_id }}/0/{{ kwargs.status }}">全部</a>
            {% endif %}

            {% for level in level_list %}
                {% if level.id == kwargs.level_id %}
                    <a href="/app/video/{{ kwargs.classification_id }}/{{ level.id }}/{{ kwargs.status }}" class="active">{{ level.title }}</a>
                {% else %}
                    <a href="/app/video/{{ kwargs.classification_id }}/{{ level.id }}/{{ kwargs.status }}">{{ level.title }}</a>
                {% endif %}
            {% endfor %}

        </div>

        <!--状态-->
        <div>
            {% if kwargs.status == 0 %}
                <a href="/app/video/{{ kwargs.classification_id }}/{{ kwargs.level_id }}/0" class="active">全部</a>
            {% else %}
                <a href="/app/video/{{ kwargs.classification_id }}/{{ kwargs.level_id }}/0">全部</a>
            {% endif %}

            {% for status in status_list %}
                {% if status.id == kwargs.status %}
                    <a href="/app/video/{{ kwargs.classification_id }}/{{ kwargs.level_id }}/{{ status.id }}" class="active">{{ status.name }}</a>
                {% else %}
                    <a href="/app/video/{{ kwargs.classification_id }}/{{ kwargs.level_id }}/{{ status.id }}">{{ status.name }}</a>
                {% endif %}
            {% endfor %}
            
        </div>
    </div>

    <div>
        <h1>结果</h1>
        <div>
            {% for video in video_list %}
                <p>{{ video.title }}</p>
                <img src="{{ video.href }}">
            {% endfor %}

        </div>
    </div>

</body>
</html>

多对多

多对多关系中主要是方向与分类之间的关系操作。

视图函数

from django.shortcuts import render, HttpResponse
from app.models import Level, Classification, Direction, Video

def video2(request, *args, **kwargs):
    """
    多对多："方向-分类
    方向：自动化、测试、运维、前端
    分类：Python、Linux、JavaScript、OpenStack、Node.js、C
    等级：初级、中级、高级、骨灰级
    """
    print(kwargs)       # {'direction_id': 1, 'classification_id': 4, 'level_id': 2}
    direction_id = kwargs.get('direction_id')
    classification_id = kwargs.get('classification_id')
    level_id = kwargs.get('level_id')
    condition = {}      # 条件    构造查询字典

    # 方向：全部列举
    direction_list = Direction.objects.all()

    # 若方向为 0，则分类显示全部
    if direction_id == 0:
        # 若分类也为 0，分类显示全部
        class_list = Classification.objects.all()
        if classification_id == 0:
            pass
        else:
            condition['classification_id'] = classification_id

    # 若方向不为 0，则根据方向查询分类
    else:
        direction_obj = Direction.objects.filter(id=direction_id)[0]
        class_list = direction_obj.classification.all()     # 根据多对多名字+方向的ID，获取相应分类列表
        # < QuerySet[ < Classification: Python >, < Classification: Linux >] >

        # 根据方向 id 获取分类的 id 列表
        vlist = direction_obj.classification.all().values_list('id')   #  < QuerySet[(1,), (5,)] >

        # 若哪个方向下没有分类
        if not vlist:
            classification_id_list = []
        else:
            # 转换为元组
            classification_id_list = list(zip(*vlist))[0]       # (1, 5)


        # 若分类为 0，则显示相应分类
        if classification_id == 0:
            condition['classification_id__in'] = classification_id_list
        else:
            if classification_id in classification_id_list:
                condition['classification_id'] = classification_id
            else:
                condition['classification_id__in'] = classification_id_list

    if level_id == 0:
        pass
    else:
        condition['level_id'] = level_id

    # 等级：全部列举
    level_list = Level.objects.all()
    video_list = Video.objects.filter(**condition)

    return render(
        request,
        'app/video2.html',
        {
            'direction_list': direction_list,
            'level_list': level_list,
            'kwargs': kwargs,
            'video_list': video_list,
            'class_list': class_list
        }
    )

模板

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>多对多和一对多</title>
    <style type="text/css">
        .box1 a {
            display: inline-block;
            padding: 5px 8px;
            border: 1px solid #dddddd;
        }

        .box1 a.active {
            background-color: coral;
            color: white;
        }
    </style>
</head>
<body>
    <div class="box1">
        <h1>筛选</h1>
        <!--方向-->
        <div>
            {% if kwargs.direction_id == 0  %}
                <a class="active" href="{% url 'video2' direction_id=0 classification_id=kwargs.classification_id level_id=kwargs.level_id %}">全部</a>
            {% else %}
                <a href="{% url 'video2' direction_id=0 classification_id=kwargs.classification_id level_id=kwargs.level_id %}">全部</a>
            {% endif %}

            {% for direction in direction_list %}
                {% if direction.id == kwargs.direction_id %}
                    <a href="{% url 'video2' direction_id=direction.id classification_id=kwargs.classification_id level_id=kwargs.level_id %}" class="active">{{ direction.name }}</a>
                {% else %}
                    <a href="{% url 'video2' direction_id=direction.id classification_id=kwargs.classification_id level_id=kwargs.level_id %}">{{ direction.name }}</a>
                {% endif %}
            {% endfor %}

        </div>

        <!--分类-->
        <div>
            {% if kwargs.classification_id == 0 %}
                <a class="active" href="{% url 'video2' direction_id=kwargs.direction_id classification_id=0 level_id=kwargs.level_id %}">全部</a>
            {% else %}
                <a href="{% url 'video2' direction_id=kwargs.direction_id classification_id=0 level_id=kwargs.level_id %}">全部</a>
            {% endif %}

            {% for class in class_list %}
                {% if class.id == kwargs.classification_id %}
                    <a class="active" href="{% url 'video2' direction_id=kwargs.direction_id classification_id=class.id level_id=kwargs.level_id %}">{{ class.name }}</a>
                {% else %}
                    <a href="{% url 'video2' direction_id=kwargs.direction_id classification_id=class.id level_id=kwargs.level_id %}">{{ class.name }}</a>
                {% endif %}
            {% endfor %}

        </div>

        <!--等级-->
        <div>
            {% if kwargs.level_id == 0 %}
                <a class="active" href="{% url 'video2' direction_id=kwargs.direction_id classification_id=kwargs.classification_id level_id=0 %}">全部</a>
            {% else %}
                <a href="{% url 'video2' direction_id=kwargs.direction_id classification_id=kwargs.classification_id level_id=0 %}">全部</a>
            {% endif %}

            {% for level in level_list %}
                {% if level.id == kwargs.level_id %}
                    <a class="active" href="{% url 'video2' direction_id=kwargs.direction_id classification_id=kwargs.classification_id level_id=level.id %}">{{ level.title }}</a>
                {% else %}
                    <a href="{% url 'video2' direction_id=kwargs.direction_id classification_id=kwargs.classification_id level_id=level.id %}">{{ level.title }}</a>
                {% endif %}
            {% endfor %}
        </div>
    </div>


    <div>
        <h1>结果</h1>
        {% for video in video_list %}
            <p>{{ video.title }}</p>
        {% endfor %}
    </div>
</body>
</html>

参考博客

• Django之组合查询
• django实现瀑布流、组合搜索、阶梯评论、验证码