编写 Model 层的代码

创建 App

这里把所有 Model 划分为三类：blog 相关、配置相关和评论相关。这么分的好处是便于独立维护各个模块，也便于在开发时分配任务。

blog App

创建一个名为 blog 的 app

此使项目的目录结构如下：

先创建博客内容相关的模型，编写 blog/models.py 中的代码

from django.contrib.auth.models import User
from django.db import models

class Category(models.Model):
    STATUS_NORMAL = 1
    STATUS_DELETE = 0
    STATUS_ITEMS = (
        (STATUS_NORMAL, '正常'),
        (STATUS_DELETE, '删除'),
    )

    name = models.CharField(max_length=50, verbose_name="名称")
    status = models.PositiveIntegerField(default=STATUS_NORMAL, choices=STATUS_ITEMS, verbose_name="状态")
    is_nav = models.BooleanField(default=False, verbose_name="是否为导航")
    owner = models.ForeignKey(User, verbose_name="作者", on_delete=models.DO_NOTHING)
    created_time = models.DateTimeField(auto_now_add=True, verbose_name="创建时间")

    class Meta:
        verbose_name = verbose_name_plural = '分类'


class Tag(models.Model):
    STATUS_NORMAL = 1
    STATUS_DELETE = 0
    STATUS_ITEMS = (
        (STATUS_NORMAL, '正常'),
        (STATUS_DELETE, '删除'),
    )

    name = models.CharField(max_length=10, verbose_name="名称")
    status = models.PositiveIntegerField(default=STATUS_NORMAL, choices=STATUS_ITEMS, verbose_name="状态")
    owner = models.ForeignKey(User, verbose_name="作者", on_delete=models.DO_NOTHING)
    created_time = models.DateTimeField(auto_now_add=True, verbose_name="创建时间")

    class Meta:
        verbose_name = verbose_name_plural = '标签'


class Post(models.Model):
    STATUS_NORMAL = 1
    STATUS_DELETE = 0
    STATUS_DRAFT = 2
    STATUS_ITEMS = (
        (STATUS_NORMAL, '正常'),
        (STATUS_DELETE, '删除'),
        (STATUS_DRAFT, '草稿'),
    )

    title = models.CharField(max_length=255, verbose_name="标题")
    desc = models.CharField(max_length=1024, blank=True, verbose_name="摘要")
    content = models.TextField(verbose_name="正文", help_text="正文必须为MarkDown格式")
    status = models.PositiveIntegerField(default=STATUS_NORMAL, choices=STATUS_ITEMS, verbose_name="状态")
    category = models.ForeignKey(Category, verbose_name="分类", on_delete=models.DO_NOTHING)
    tag = models.ManyToManyField(Tag, verbose_name="标签")
    owner = models.ForeignKey(User, verbose_name="作者", on_delete=models.DO_NOTHING)
    created_time = models.DateTimeField(auto_now_add=True, verbose_name="创建时间")

    class Meta:
        verbose_name = verbose_name_plural = "文章"
        ordering = ['-id']      # 根据id进行降序排列

config APP

接下来，创建另外一个 config APP，它用来放置其他几个模型，blog App 用来放内容相关的数据，这个用来放配置相关的数据——侧边栏和友链。创建好之后，编写 config/models.py 中的代码：

from django.contrib.auth.models import User
from django.db import models

class Link(models.Model):
    STATUS_NORMAL = 1
    STATUS_DELETE = 0
    STATUS_ITEMS = (
        (STATUS_NORMAL, '正常'),
        (STATUS_DELETE, '删除'),
    )
    title = models.CharField(max_length=50, verbose_name="标题")
    href = models.URLField(verbose_name="链接")  # 默认长度200
    status = models.PositiveIntegerField(default=STATUS_NORMAL, choices=STATUS_ITEMS, verbose_name="状态")
    weight = models.PositiveIntegerField(default=1, choices=zip(range(1, 6), range(1, 6)),
                                         verbose_name="权重",
                                         help_text="权重高展示顺序靠前")

    owner = models.ForeignKey(User, verbose_name="作者", on_delete=models.DO_NOTHING)
    created_time = models.DateTimeField(auto_now_add=True, verbose_name="创建时间")

    class Meta:
        verbose_name = verbose_name_plural = "友链"


class SideBar(models.Model):
    STATUS_SHOW = 1
    STATUS_HIDE = 0
    STATUS_ITEMS = (
        (STATUS_SHOW, '展示'),
        (STATUS_HIDE, '隐藏'),
    )
    SIDE_TYPE = (
        (1, 'HTML'),
        (2, '最新文章'),
        (3, '最热文章'),
        (4, '最近评论'),
    )
    title = models.CharField(max_length=50, verbose_name="标题")
    display_type = models.PositiveIntegerField(default=1, choices=SIDE_TYPE,
                                               verbose_name="展示类型")
    content = models.CharField(max_length=500, blank=True, verbose_name="内容",
                               help_text="如果设置的不是HTML类型，可为空")

    status = models.PositiveIntegerField(default=STATUS_SHOW, choices=STATUS_ITEMS, verbose_name="状态")
    owner = models.ForeignKey(User, verbose_name="作者", on_delete=models.DO_NOTHING)
    created_time = models.DateTimeField(auto_now_add=True, verbose_name="创建时间")

    class Meta:
        verbose_name = verbose_name_plural = "侧边栏"

comment APP

最后，创建评论部分，这是一个可以完全独立的模块。编写 comment/models.py 的代码：

from django.db import models
from blog.models import Post

class Comment(models.Model):
    STATUS_NORMAL = 1
    STATUS_DELETE = 0
    STATUS_ITEMS = (
        (STATUS_NORMAL, '正常'),
        (STATUS_DELETE, '删除'),
    )
    target = models.ForeignKey(Post, verbose_name="评论目标")
    content = models.CharField(max_length=2000, verbose_name="内容")
    nickname = models.CharField(max_length=50, verbose_name="昵称")
    website = models.URLField(verbose_name="网站")
    email = models.EmailField(verbose_name="邮箱")
    status = models.PositiveIntegerField(default=STATUS_NORMAL, choices=STATUS_ITEMS, verbose_name="状态")
    created_time = models.DateTimeField(auto_now_add=True, verbose_name="创建时间")

    class Meta:
        verbose_name = verbose_name_plural = "评论"

到此为止，Model 部分已经实现完毕。

配置 INSTALLED_APPS

创建好 App，编写好对应的 Model 代码之后，我们需要把这些 App（blog、config 和 comment）放到 settings配置中，才能让 Django 启动时识别这些 App。

修改 settings/base.py：

INSTALLED_APPS = [
    'blog',
    'config',
    'comment',
    
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
]

创建数据库[表]

配置好 Model 和 App 之后，需要做的就是配置数据库。

这意味着已经创建好了迁移文件。至此 Model 和数据库就创建完成了，可以通过工具查看表信息。