save_deep

This package first saves all the children of the given oject and then the object itself. It solves the error: ValueError: save() prohibited to prevent data loss due to unsaved related object '<<foreign_object>>'.

Note: it does not work (yet) with circular dependencies

Example

Say you have this this model

class Company(models.Model):
    name = models.CharField(max_length=256)

class Employee(models.Model):
    username = models.CharField(max_length=256)
    company = models.ForeignKey(Company, on_delete=models.CASCADE)

If you try to do

Employee(username='tom', company=Company(name='some-name')).save()

you get

ValueError: save() prohibited to prevent data loss due to unsaved related object '<<foreign_object>>'.

But if you use save_deep, the company is saved first, then the employee

employee = save_deep(Employee(username='tom', company=Company(name='some-name')))

This works with a deeply nested object-tree and with updates (and update/create-mixes) as well as long as there are no circular dependencies.