django中此字段为必填错误 [英] This field is required error in django

问题描述

在我设置的模型中：

class Task(models.Model):
    EstimateEffort = models.PositiveIntegerField('Estimate hours',max_length=200)
    Finished = models.IntegerField('Finished percentage',blank=True)

但是在网页中，如果我没有为 Finished 字段设置值，则会显示错误此字段为必填项。我尝试了 null = True 和 blank = True 。但是他们都不起作用。所以，请您告诉我如何使字段允许为空。

But in the web page, if I didn't set a value for the Finished field, it is showing an error This field is required. I tried null=True and blank=True. But none of them worked. So could you please tell me how can I make a field allowed to be empty.

我发现有一个属性 empty_strings_allowed ，我将其设置为True，但仍保持不变，并且将models.IntegerField子类化。仍然无法正常工作

I have found that there is a attribute empty_strings_allowed, i set it to True, but still the same, and i subclass the models.IntegerField. It still can not work

class IntegerNullField(models.IntegerField):
    description = "Stores NULL but returns empty string"
    empty_strings_allowed =True
    log.getlog().debug("asas")
    def to_python(self, value):
        log.getlog().debug("asas")
        # this may be the value right out of the db, or an instance
        if isinstance(value, models.IntegerField):
            # if an instance, return the instance
            return value
        if value == None:
            # if db has NULL (==None in Python), return empty string
            return ""
        try:
            return int(value)
        except (TypeError, ValueError):
            msg = self.error_messages['invalid'] % str(value)
            raise exceptions.ValidationError(msg)

    def get_prep_value(self, value):
        # catches value right before sending to db
        if value == "":
            # if Django tries to save an empty string, send to db None (NULL)
            return None
        else:
            return int(value) # otherwise, just pass the value

推荐答案

使用

Finished = models.IntegerField('Finished percentage', blank=True, null=True)

阅读 https ：//docs.djangoproject.com/zh-CN/1.4/ref/models/fields/#blank ：

null纯粹是空的与数据库相关，而空白与验证相关。

您可能已经定义了没有 null = True <的字段/ code>首先。现在，更改代码中的内容将不会更改数据库的初始布局。使用南进行数据库迁移或手动更改数据库。

You might have defined the field without null=True first. Changing that in the code now won't change the initial layout of the database. Use South for database migrations or change the database manually.

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