许多关系与关系的附加数据有很多关系 [英] Many to many relationships with additional data on the relationship

问题描述

我正在尝试创建一个记录我所有漫画购买的django数据库，我遇到了一些问题。我试图模仿一个漫画问题和与之相关的艺术家之间的关系。

I'm trying to create a django database that records all my comic purchases, and I've hit a few problems. I'm trying to model the relationship between a comic issue and the artists that work on it.

漫画问题有一个或多个艺术家在这个问题上工作，一个艺术家将致力于一个以上的问题。此外，艺术家还有他们在漫画创作者（所有关于这个问题的工作），作家（写剧本），抽屉（绘制完整的漫画），铅笔，油墨，颜色或文字上所做的工作，并且可能有几个艺术家在给定的角色。

A comic issue has one or more artists working on the issue, and an artist will work on more than a single issue. In addition, the artist has a role relating to what they did on the comic – creator (all the work on that issue), writer (wrote the script), drawer (drew the complete comic), pencils, inks, colours or text, and there may be several artists in a given role.

这给我一个数据库模型，如：

This gives me a database model like:

然后我将其转换为以下Django模型。
由于我需要关于关系的其他数据，我相信我必须使用一个单独的类来处理关系，并持有额外的

I then translate this into the following Django model. As I require additional data on the relationship, I believe I have to use a separate class to handle the relationship, and hold the additional

class Artist(models.Model):
    name = models.CharField(max_length = 100)

    def __unicode__(self):
        return self.name

class ComicIssue(models.Model):
    issue_number = models.IntegerField()
    title = models.TextField()
    artists = models.ManyToManyField(Artist, through='IssueArtist')

    def __unicode__(self):
        return u'issue = %s, %s' % (self.issue_number, self.title)

class IssueArtist(models.Model):
    roles = ( (0, "--------"),
              (1, "Creator"),
              (2, "Writer"),
              (3, "Drawer"),
              (4, "Pencils"),
              (5, "Inks"),
              (6, "Colours"),
              (7, "Text"),
            )
    artist = models.ForeignKey(Artist)
    issue = models.ForeignKey(ComicIssue)
    role = models.IntegerField(choices = roles)

我的问题是：

1）这似乎是一个正确的建模方式吗？

1) Does this seem a correct way of modelling this?

2）如果我不使用 through ='IssueArtist'功能，我可以使用 artists.add添加关系（）函数。如果我使用这个，我会收到一个错误'ManyRelatedManager'对象没有属性'add'。我必须通过创建 IssueArtist（）实例来手动管理关系，并明确地搜索关系表？
NB。我正在使用Django 1.0，目前

2) If I don't use the through='IssueArtist' feature, I can add relationships by using the artists.add() function. If I do use this, I get an error 'ManyRelatedManager' object has no attribute 'add'. Do I have to manually manage the relationship by creating IssueArtist() instances, and explicitly searching the relationship table? NB. I am using Django 1.0, at the moment

推荐答案

我建议您查看多个地方的多个地方关系在 Django文档 - 它涵盖了你的问题。

I recommend you check out the section "EXTRA FIELDS ON MANY-TO-MANY RELATIONSHIPS" in the Django documentation - it covers exactly your question.

1：是的，创建中介模型是要走的路。

1: yes, creating an intermediary model is the way to go.

2：从文档中： 与正常的多对多领域不同，您不能使用添加，创建或分配来创建关系 - 而是将艺术家添加到问题中，从中介模型中执行：

2: From the documentation: "Unlike normal many-to-many fields, you can't use add, create, or assignment to create relationships" - Instead, for adding Artist to an Issue, do it from the intermediary model:

some_artist = Artist.objects.get(name='some name')
some_issue = Issue.objects.get(tile='some tite')
IssueArtist.objects.create(artist= some_artist, issue = some_issue, role=1)

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