Question

这是我的django模型
因为我有ProjectsArchive和StatusArchive来保存历史数据你可以看到很多字段都是重复的我想知道如何减少重复代码以使代码简单

class Projects(models.Model):
    title      = models.CharField(max_length=255, blank=True)
    link       = models.CharField(max_length=300, blank=True)
    state      = models.CharField(max_length=30, blank=True)
    update_at  = models.DateTimeField(auto_now=True, blank=True, null=True)
    ....

class ProjectsArchive(models.Model):
    title      = models.CharField(max_length=255, blank=True)
    link       = models.CharField(max_length=300, blank=True)
    state      = models.CharField(max_length=30, blank=True)
    update_at  = models.DateTimeField(auto_now=True, blank=True, null=True) 
    ....

class Status(models.Model):
    project             = models.ForeignKey(Projects, null = True, blank = True)
    state               = models.CharField(max_length=255, blank=True)
    crawl_update_at     = models.DateTimeField(auto_now=True, blank=True, null=True)    
    ....
class StatusArchive(models.Model):
    project             = models.ForeignKey(ProjectsArchive, null = True, blank = True)
    state               = models.CharField(max_length=255, blank=True)
    crawl_update_at     = models.DateTimeField(auto_now=True, blank=True, null=True)  
    ....

Answer 1

您可以在此处参考：Abstract base classes

根据你的问题，我会这样做：

class BasicInfo(models.Model):
    title      = models.CharField(max_length=255, blank=True)
    link       = models.CharField(max_length=300, blank=True)
    state      = models.CharField(max_length=30, blank=True)
    update_at  = models.DateTimeField(auto_now=True, blank=True, null=True) 

    class Meta:
        abstract = True

class Projects(BasicInfo):
    ....

class ProjectsArchive(BasicInfo):
    ....

完成BasicInfo后，您可以重复使用title，link，state和update_at。

但是，我们可以为state和crawl_update_at创建包含Status和StatusArchive的通用模型。

class StatusInfo(models.Model):
    state               = models.CharField(max_length=255, blank=True)
    crawl_update_at     = models.DateTimeField(auto_now=True, blank=True, null=True) 

    class Meta:
        abstract = True

class Status(StatusInfo):
    project             = models.ForeignKey(Projects, null = True, blank = True)
    ....

class StatusArchive(StatusInfo):
    project             = models.ForeignKey(ProjectsArchive, null = True, blank = True)
    ...

Answer 2

您可以创建一个CommonModel，您可以在其中放置冗余字段，然后在继承CommonModel而不是models.Model的情况下使用您想要使用它们的模型。

class CommonModel(models.Model):
    class Meta:
        abstract = True

    title      = models.CharField(max_length=255, blank=True)
    link       = models.CharField(max_length=300, blank=True)
    state      = models.CharField(max_length=30, blank=True)
    update_at  = models.DateTimeField(auto_now=True, blank=True, null=True)

class ProjectArchive(CommonModel):
      any_new_field_you_want_to_add

Answer 3

您正在寻找的是抽象元课程。

https://docs.djangoproject.com/en/1.8/topics/db/models/

class ProjectTemplate(models.Model):
    title      = models.CharField(max_length=255, blank=True)
    link       = models.CharField(max_length=300, blank=True)
    state      = models.CharField(max_length=30, blank=True)
    update_at  = models.DateTimeField(auto_now=True, blank=True, null=True)
    ....

    class Meta:
        abstract = True

class Projects(ProjectTemplate):
    pass


class ProjectsArchive(ProjectTemplate):
    pass

Answer 4

您可以使用继承。请查看以下链接

django abstract models versus regular inheritance

这也是django关于模型的文档（看看抽象基类）

https://docs.djangoproject.com/en/1.8/topics/db/models/

django模型减少重复代码

4 个答案: