How to associate quantity amount in Django's many to many relationship-CodePudding

In Django I have 2 models. One called Box and one called Product. A Box can have many different products and with different quantities of each product. For example box1 can have 1 productA and 2 productB.

My box model

class Box(models.Model):
    boxName = models.CharField(max_length=255, blank = False)
    
    product = models.ManyToManyField(Product)

    def __str__(self):
        return self.boxName

My product model

class Product(models.Model):
        productName = models.CharField(max_length=200)
        productDescription = models.TextField(blank=True)
        productPrice = models.DecimalField(max_digits=9, decimal_places=0, default=0)

    
    class Meta:
        db_table = 'products'
        ordering = ['-productName']

    def __str__(self):
        return self.productName

How do I set up this model allowing me to select quantity of a products when creating the box object?

CodePudding user response：

Define a new model that contains product quantity.

class Box(models.Model):
    boxName = models.CharField(max_length=255, blank = False)
    product_set = models.ManyToManyField(ProductSet)

    def __str__(self):
        return self.boxName

class ProductSet(models.Model):
    quantity = models.PositiveIntegerField()
    product = models.ForeignKey(Product, on_delete = models.PROTECT)

class Product(models.Model):
    productName = models.CharField(max_length=200)
    productDescription = models.TextField(blank=True)
    productPrice = models.DecimalField(max_digits=9, decimal_places=0, default=0)

    
    class Meta:
        db_table = 'products'
        ordering = ['-productName']

    def __str__(self):
        return self.productName