Question

I’d like to make a custom save method on a model that combines values from two of it’s other fields, one of which is a value stored in a foreign key relation.

For instance, given this model:

class Post(models.Model):
    text = charfield()
    date = datefield()
    user = ForeignKey(other model)
    key = integerfield()
    unique = charfield()

I’d like to be able to save the field titled unique as a combination of both the user username from the foreign key, and the key field, which is an auto-incrementing integer field. Is something like this possible? I searched for similar questions but couldn’t find any.

Answer 1

The thing is of course that you won’t have a key until you’ve saved the model at least once. So your save method will need to call the superclass save, get the key, set the unique field, then save again.