CODEWITHSUNDEEP
pythondjangosqlite
robotHamster
robotHamster

Reputation: 649

Django Models: Linking recipes and keeping track of quantities

Problem Description

Suppose I have a database with multiple models running with a Django front-end.

One of the tables in the Inventory. The inventory consists of entries with the following specifications:

class InventoryItem(models.Model):
    item_name = models.TextField(max_length=10) #apple, orange, cilantro, etc...
    item_quantity = models.DecimalField(...)

The next model will be to describe what is made with those ingredients

class Product(models.Model):
    product_name = models.TextField(...)
    product_description = models.TextField(...)

The ProductItem model also needs to keep track of the ingredients taken from inventory by specifying the InventoryItem and the quantity used from that inventory item used.

Previous Experience

In a previous experience, I have done something similar with EntityFramework in C# with MySQL. The way I achieved that was using another table/model called RecipeElement, where each one of those would be foreign-keyed to a ProductItem entry. The RecipeElement model looked like the following:

class RecipeElement(models.Model):
    inventory_item = models.ForeignKey(InventoryItem, on_delete = models.CASCADE)
    quantity_used = models.DecimalField(...)
    product_item = models.ForeignKey(ProductItem, on_delete = models.CASCADE)

The Issue

My issue with that approach in Django is twofold:

  1. How would I retrieve the RecipeElement entries associated with a ProductItem entry
  2. How would the user input the RecipeElement entries and the ProductItem entries on one page. (The number of RecipeElements for each ProductItem is not limited, but each RecipeElement is associated with only one ProductItem

I am using SQLite for the moment but plan to transfer to MySQL in the future, if that changes anything.

Upvotes: 0

Views: 436

Answers (1)

Mauricio Cortazar
Mauricio Cortazar

Reputation: 4213

If you want to retrieve all the RecipeElement for a Product do something like:

ProductItem.objects.get(pk=1).recipeelement_set.all()

In the second issue you can add a recipeElement from a product using .add() or create() like:

ProductItem.objects.get(pk=1).recipeelement_set.add(your_recipe_element)

Upvotes: 1

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