调试Django管理面板错误

Question

When I navigate to the admin interface for a particular model (the whole-table view), and simply hit 'Save', this error was popping up on the usual red banner:

Please correct the errors below.

Needless to say I couldn't actually make edits from this view, until I experimented and fixed it.

Here's my class:

 class RoleMapping(models.Model):
     MIN_LENGTH, MAX_LENGTH = 3, 40
     role_name = models.CharField(unique=True, max_length=MAX_LENGTH, validators = [
         MinLengthValidator(MIN_LENGTH, "Field length should be greater than {}".format(MIN_LENGTH))
     ])
     role_type = models.ForeignKey(RoleType, null=True, blank=True )

Here's the admin interface model. But, flipping around some of the editable fields seems to have made things work.

 class RoleMapping(admin.ModelAdmin):
     model = RoleMapping
     list_display = ('role_name', 'role_type',)
     #list_editable = ('role_name', 'role_type',) # This fails
     #list_editable = ('role_name',) # This fails
     list_editable = ('role_type',) # This works?!

I can get it working, pretty easily, by keeping role_type as the only editable type. However, I only found this out after a bit of trial and error. I'm wondering:

1. What's the django way of debugging these sorts of admin-panel-ORM issues in the future

2. Why might it have been failing in the first place?

Answer 1

According to the Django admin docs :

Note: list_editable interacts with a couple of other options in particular ways; you should note the following rules:

• Any field in list_editable must also be in list_display . You can't edit a field that's not displayed!
• The same field can't be listed in both list_editable and list_display_links – a field can't be both a form and a link.

You'll get a validation error if either of these rules are broken.

My guess is that you are violating the second point and that role_name is by default the sole member of list_display_links .

To test this, set list_display_links = None or make another field and add it to list_display and list_display_links .

Edit:

I suspect that the following will give you what you want. I've simply added id as the first element of list_display . Behind the scenes, this adds id instead of role_name to list_display_links , which frees up role_name to be allowed in list_editable .

class RoleMapping(admin.ModelAdmin):
     model = RoleMapping
     list_display = ('id', 'role_name', 'role_type',)
     list_editable = ('role_name', 'role_type',)