Django模型引用其他类的对象 [英] django model referencing object from other class

问题描述

您好，对于django来说还很新，但是考虑到以下模型及其关系，我如何为该对象创建一个只读字段，该字段是对另一个类中字段的引用?我已经在stackoverflow上寻找了一段时间，但是不确定是什么样的模型引用.

Hi there pretty new to django but considering the below models, with their relationships, how do I create a read only field for the object that is a reference to a field in another class? I've looked for a while on stackoverflow, but not sure what kind of model reference that would be.

这的基本逻辑是:我有一个位于服务器机房地板上的服务器机架，并将其与机架位置相关联，并排成一行以管理功耗和其他物品.仅供最终用户参考，我想要一个只读字段来向他们显示此机架所处的行，以及该机架派生自机架位置.我一直在摆弄一个方法来查找它，但似乎无法弄清楚语法或在django管理页面上找到相关的内容.

The basic logic for this being: I have this server rack that sites on a floor in a server room, and I'm associating it to a rack position, and row to manage power consumption and other goodies. Just for my end-user's reference I want a read only field to show them what row this rack lives in, and its derived from the rack position. I'd been fiddling around with creating a method to look it up, but can't seem to figure out the syntax or find something related on the django admin pages.

任何想法都将受到高度赞赏，因为我一直盯着文档，我真的可以使用该帮助，而且似乎无法为此找到相关的模型参考.

Any ideas would be super appreciated, I really could use the help as I've been staring through docs forever, and can't seem to find a relevant model reference for this.

class rack(models.Model):
    class Meta:
        verbose_name = "Rack"
        verbose_name_plural = "Racks"

    def __unicode__(self):
        return str(self.position)

    def row(self, obj):
        return self.position.row

    position = models.OneToOneField("rackposition")
    row = row(position.row.row)
    asstag = models.CharField("Asset Tag", max_length=200, unique=True)
    rackunits = models.IntegerField("Rack Units")

class rackposition(models.Model):
    class Meta:
        verbose_name = "Rack Position"
        verbose_name_plural = "Rack Positions"

    def __unicode__(self):
        return str(self.position)

    position = models.CharField("Position", max_length=35, primary_key=True)
    row = models.ForeignKey("row")

class row(models.Model):
    class Meta:
        verbose_name = "Row"
        verbose_name_plural = "Rows"

    def __unicode__(self):
        return str(self.row) + "." + str(self.suite)

    row = models.CharField("Row ID", max_length=200, unique=True)
    suite = models.ForeignKey(suite, blank=False)
    power_budget = models.IntegerField("Power Budget")
    power_volt = models.IntegerField("Power Voltage")
    dual_bus = models.BooleanField("Dual Bus", default=False)

推荐答案

您不需要方法.假设您有一个名为 my_rack 的机架实例，则可以通过 my_rack.position.row 获得其行.

You don't need a method. Assuming you have a rack instance called my_rack, you can get its row with my_rack.position.row.

注意，您应该真正遵循PEP8，并使用CamelCase作为类名.

Note, you should really follow PEP8 and use CamelCase for your class names.

如果要在管理员中将其视为只读字段，则需要在模型或ModelAdmin类上定义一个方法.例如:

If you want to see it as a readonly field in the admin, you will need to define a method either on the model or on the ModelAdmin class. For example:

class RackAdmin(admin.ModelAdmin):
    model = Rack
    readonly_fields = ('row',)

    def row(self, obj):
        return obj.position.row

这篇关于Django模型引用其他类的对象的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！