Flask remove items from another table - flask

Question

I have a db with recipes and ingredients:
class Recipe(db.Model):
id = db.Column(db.Integer, primary_key=True)
ingredient = db.relationship('Ingredient', backref='ingredientrecipe', lazy=True)
recipe_name = db.Column(db.String(100), nullable=False)
class Ingredient(db.Model):
id = db.Column(db.Integer, primary_key=True)
recipe_id = db.Column(db.Integer, db.ForeignKey('recipe.id'), nullable=False)
name = db.Column(db.String(100))
The ingredients are listed within an html table. (For clarity, I've not included the full Bootstrap html for the modal, although it's exhibiting a bit of weird behaviour despite a unique id)
<table class="table">
<thead>
<tr>
<th scope="col">#</th>
<th scope="col">Name</th>
</tr>
</thead>
<tbody>
{% for ingredient in ingredient.items %}
<tr class="ingredient">
<th scope="row"> {{ hop.id }} </th>
<td>{{ ingredient.name }}</td>
<td>
<modal html here>
<form action="{{ url_for('deleteingredient', ingredient_id=ingredient.id, recipe_id=ingredient.recipe_id) }}" method="POST">
<input class="btn btn-danger" type="submit" value="Delete">
</form>
</modal html>
{% endfor %}
</tr>
</tbody>
</table>
And here's my delete route:
#app.route('/recipe/<int:ingredient_id>/delete', methods=['POST'])
#login_required
def deleteingredient(ingredient_id):
recipe = Recipe.query.get_or_404(recipe_id)
ingredient = Ingredient.query.filter_by(ingredientrecipe=recipe)
if recipe.author != current_user:
abort(403)
db.session.delete(ingredient)
db.session.commit()
flash('Your ingredient has been deleted', 'success')
I'm not going to post the error message that comes up when I try to do this as I think it's unrelated (it's a (sqlite3.IntegrityError) NOT NULL constraint failed on a different table related to recipe) and potentially will confuse the issue.
Wanted behaviour is to go to a single recipe page, click on a button on a single row of a list of ingredients, for a modal to pop up, and a single ingredient row to be deleted from the database.
I'm pretty sure this is down to me not comprehending the logic behind the database structure and how the routes work with related tables. Any help in reducing my brain damage would be much appreciated!

Answer 1

By looking at your code, I can spot some issues that could break the logic:
You never use ingredient_id in your deleteingredient function
recipe_id is not defined
What is the purpose of the ingredient relationship in Recipe model? Since a recipe has several ingredients and an ingredient can have several recipes, it's a n-n relationship. Maybe you should consider looking at this

Answer 2

This is the code that got it working this morning.
The issue I had with the NOT NULL was due to the route being the same address as the delete recipe route, so it was doing the same thing. I thought it was a modal problem so spent some time researching Bootstrap modals, turns out I had everything right on the frontend.
Adding the ingredient line I started getting some proper debug information and it was relatively straightforward from there.
#app.route('/recipe/ingredient/<int:ingredient_id>/delete', methods=['POST'])
#login_required
def deleteingredient(ingredient_id):
ingredient = Ingredient.query.get_or_404(ingredient_id)
db.session.delete(ingredient)
db.session.commit()
flash('Your ingredient has been deleted', 'success')
return redirect(url_for('recipe', recipe_id=ingredient.recipe_id))