CODEWITHSUNDEEP
djangodjango-modelstastypie
Eugene Goldberg
Eugene Goldberg

Reputation: 15524

How to deal with many-to-many in django / tastypie

I have the following two models, that should have many-to-many between them:

class Blueprint(models.Model):
    name = models.CharField(max_length=120)
    description = models.TextField()

    class Meta:
        ordering = ["name", ]


class Workload(models.Model):
    blueprints = models.ManyToManyField('Blueprint', db_constraint=False)
    name = models.CharField(max_length=120)
    description = models.TextField()
    image = models.CharField(max_length=120)
    flavor = models.CharField(max_length=120)

    class Meta:
        ordering = ["name", ]

Being totally new to django and tastypie, I have a couple of questions:

1) What is the proper syntax to specify many-to-many between the Blueprint and Workload, so when a new Blueprint record is created, it does not run into a database constrains, complaining that the related Workload record can not be empty

2) What is the proper syntax for my api.py, to have the related Workload link as a part of GET /api/blueprint/1 output, as well as to have a Blueprint link as a part of GET /api/workload/1 output

I would imagine, that having many-to-many is very common to django / tastypie apps, and it has been solved long ago, but, I was unable to find a clean solution to this (and I'new :)

Upvotes: 0

Views: 102

Answers (1)

warath-coder
warath-coder

Reputation: 2122

Not sure what issues you are having, but you should add primary keys to each model, typically an auto int field.

class Blueprint(models.Model):
    id = models.AutoField(primary_key=True)
    name = models.CharField(max_length=120)
    description = models.TextField()

    class Meta:
        ordering = ["name", ]


class Workload(models.Model):
    id = models.AutoField(primary_key=True)
    blueprints = models.ManyToManyField('Blueprint', db_constraint=False)
    name = models.CharField(max_length=120)
    description = models.TextField()
    image = models.CharField(max_length=120)
    flavor = models.CharField(max_length=120)

    class Meta:
        ordering = ["name", ]

You should be able to create a blueprint without a workload. However, with current syntax you Can Not have a workload without a blueprint assigned. If you want to allow workloads with no blueprint, then add null=True, blank=True to that field.

as for the url; there is tons of posts on here that show how to setup a url like your asking.

Upvotes: 1

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