Question

不想询问是否可以在CharField字段中使用populate_from选项来预填充其他字段中的字段，就像slug字段的示例一样。

class Post(models.Model):
    ***name***= models.CharField(max_length=50)
    slug = extension_fields.AutoSlugField(populate_from='***name***', blank=True)
    created = models.DateTimeField(auto_now_add=True, editable=False)
    last_updated = models.DateTimeField(auto_now=True, editable=False)

让我们说，

class Employee(models.Model):
    eid= models.CharField(primary_key = True)
    lastname = models.CharField(max_length=50)
    firstname = models.CharField(max_length=50)
    middlename = models.CharField(max_length=50, null=True)

现在我不想添加新的CharField全名。我想要从姓氏，名字和中间名字段填充全名。

fullname = models.CharField(populate_from = "***i don't know what to do here***")

请帮忙......

Answer 1

您可以在Employee模型的保存方法中执行此操作。

def save(self, *args, **kwargs):
    self.fullname = '{0} {1} {2}'.format(self.firstname, self.middlename, self.lastname)
    super(Employee, self).save(*args, **kwargs)

为此，您可能必须将fullname字段保留为可选字段。否则，您可能会在表单中遇到错误。

Answer 2

这可能是一个解决方案，没有populate_from

class Employee(models.Model):
    eid= models.CharField(primary_key = True)
    lastname = models.CharField(max_length=50)
    firstname = models.CharField(max_length=50)
    middlename = models.CharField(max_length=50, null=True)
    fullname = models.CharField(max_length=50)

    def save(self):
        self.fullname = "%s %s %s" % (lastname, firstname, middlename)
        super(Employee, self).save()

或使用AutoSlugField和 populate_from

class Employee(models.Model):
    eid= models.CharField(primary_key = True)
    lastname = models.CharField(max_length=50)
    firstname = models.CharField(max_length=50)
    middlename = models.CharField(max_length=50, null=True)
    fullname = AutoSlugField(populate_from=lambda instance: instance.employee.get_full_name())

    def get_full_name(self):
        fullname = "%s %s %s" % (lastname, firstname, middlename)
        return fullname

Answer 3

这是一个不需要覆盖save函数的选项：

class Employee(models.Model):

    def get_fullname(self):
        return '{} {} {}'.format(self.lastname, self.firstname, self.middlename)

    eid= models.CharField(primary_key = True)
    lastname = models.CharField(max_length=50)
    firstname = models.CharField(max_length=50)
    middlename = models.CharField(max_length=50, null=True) 
    fullname = property(get_fullname)

如果您不需要fullname lastname，firstname和middlename分别编辑def my_process_executor(req, semaphore=None): try: p = multiprocessing.Process(target=do_stuff,args=(req,)) p.daemon = False p.start() p.join(MAX_SECONDS_WAITING_FOR_PROCESS) if p.is_alive(): # Too much time running, kill it! p.terminate() p.join() finally: if semaphore: semaphore.release()该选项，因为它不会显示为管理员中的字段，但~~将结果存储在数据库中~~在调用时获取值

Django模型字段 - CharField的populate_from选项

3 个答案: