Handling Foreign Keys in the Django-Import-Export Plugin

Preface

Django-Import-Export is a very useful and convenient Django data import/export plugin that integrates perfectly with the Django Admin backend. With just a small amount of code configuration, you can easily implement import and export in various formats as needed. For more on how to use this plugin, you can check my previous article: put the article link here

Previously when using it, I always created a dedicated raw data table to store the imported data, then did some data processing on the raw data table and stored the data in other tables before it could actually be used. (Doesn't seem like a great approach)

Now what I need is to import data based on the existing table structure, and the table I need to import data into also has several foreign keys, which involves handling foreign keys.

So I searched online for a long time (Google-oriented programming). Domestic materials mainly consist of the two articles in the references. After looking at them, they solved it with somewhat fancy hacky tricks, which felt so-so. That kind of hack couldn't satisfy me, so I gave up on Google and went straight to grinding through the official docs (I really regret why I didn't just grind through the official docs from the start...)

Solution

The real solution still has to come from the official documentation.

Model Configuration

First let's see how the models are defined. I'll put the official examples here; my own project's model has too many fields, so looking at the official ones is clearer.

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

    def __str__(self):
        return self.name


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

    def __str__(self):
        return self.name


class Book(models.Model):
    name = models.CharField('Book name', max_length=100)
    author = models.ForeignKey(Author, blank=True, null=True)
    author_email = models.EmailField('Author email', max_length=75, blank=True)
    imported = models.BooleanField(default=False)
    published = models.DateField('Published', blank=True, null=True)
    price = models.DecimalField(max_digits=10, decimal_places=2, null=True, blank=True)
    categories = models.ManyToManyField(Category, blank=True)

    def __str__(self):
        return self.name

Resource Configuration

For more on Resource configuration, you can refer to the official documentation. If you don't want to grind through the docs, you can check my previous article: article link

from import_export import fields, resources
from import_export.widgets import ForeignKeyWidget

class BookResource(resources.ModelResource):
    author = fields.Field(
        column_name='author',
        attribute='author',
        widget=ForeignKeyWidget(Author, 'name'))

    class Meta:
        fields = ('author',)

Done. This way, during import it will automatically associate the foreign key author.

References

• Official documentation: https://django-import-export.readthedocs.io/en/latest/api_widgets.html#import_export.widgets.ForeignKeyWidget
• Django-10 Import/Export Feature Optimization: https://www.jianshu.com/p/f82a465a41d8
• A method for django-import-export related foreign keys import/export in admin: https://blog.csdn.net/weixin_38496380/article/details/104717236

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