带有MySQL的Django：DatabaseError（1406，“第1行的列'名称'的数据太长了”）

Question

I have a Django webapp, currently been testing with SQLite but now want to deploy and use MySQL, and I'm getting this error.

I am getting this error right when using python manage.py syncdb :

You just installed Django's auth system, which means you don't have any superusers defined.
Would you like to create one now? (yes/no): no
DatabaseError: (1406, "Data too long for column 'name' at row 4")

And also when trying to create a Store object (one of the models) with this code:

store_leicester = Store.objects.create(
    name='Hugo Boss UK Store Leicester Square',
    country='United Kingdom',
    district='London',
    catalog=catalog ...
)

Error:

DatabaseError at /populate/
(1406, "Data too long for column 'name' at row 1")

Store model, for example, is:

class Store(models.Model):
    """
    Class for a Store.
    """

    name = models.TextField(max_length=128)

    country = models.TextField(max_length=64)
    district = models.TextField(max_length=64)

    catalog = models.OneToOneField('ShopCatalog', related_name='shop', null=True)
    chain = models.ForeignKey('StoreChain', related_name="shops", null=True)

Now naturally, these 10-15 characters of text are not above the 128 character limit, so there is something else going on. Starting by the fact the error also comes up on syncdb.

I'm using two Django packages I created myself that use models, but I don't think that is the problem here.

Default collation on schema was latin-1 but I tried switching to utf-8 and still exactly same error.

Thank you

Answer 1

When you syncdb , Django also stores the verbose name of your model in its internal django_content_type table. That table has a limit of (as of Django 1.2) 100 characters. Having a model whose verbose name is over 100 characters will cause the problem you are experiencing.

Check if your app has any other models with a long name/ verbose_name , and try shortening them. That should fix the problem. ( Store doesn't seem long at all, but perhaps there's a different model you didn't mention.)

By the way, the reason you didn't see this with SQLite is that if I remember correctly SQLite doesn't enforce length restrictions on char fields.