[FIXED] MongoDB: deleting an array value in multiple documents in one collection using pymongo

Issue

Afternoon all. I hope you can help with a problem. I am using creating a Flask app and using pymongo and I need to delete a singular array value from multiple arrays across many documents within one collection. I have recipe documents within a 'recipes' collection, and within each of them is an array ('category') that can be between 1 and 3 values in length. I have a feature available within the admin section of my site that allows for the deletion of a category from the 'categories' collection and so, to go with that, I want to delete any instances of that category value within the 'category' array on any recipe document within the recipes 'collection'.

I have managed to do this on a single document:

mongo.db.recipes.update(
        {"_id": ObjectId("60df2eec9df14e58d0c698c8")},
        {"$pull": {"category": category_id}}
    )

but have not managed this on the collection as a whole I have determined I need to use the $all with the $pull operator on the collection using the 'update_many' query and have so far tried:

mongo.db.recipes.update_many({"category": {"$all": {"$pull": {"category": category_id}}}})

mongo.db.recipes.update_many({"$all": {"$pull": {"category": category_id}}})

mongo.db.recipes.update_many({"category": {"$pullAll": {"category": category_id}}})

None of them work. I keep getting a the error:

TypeError: update_many() missing 1 required positional argument: 'update'

Any help would be appreciated.

Solution

Read - https://pymongo.readthedocs.io/en/stable/api/pymongo/collection.html?highlight=update_many#pymongo.collection.Collection.update_many

1st parameter is filter which will be {} if you want to update all document

mongo.db.recipes.update_many(
  {} // filter filter,
  {} // update
)

---

mongo.db.recipes.update_many({ }, {"$pull": {"category": category_id}})

Answered By - Tushar Gupta - curioustushar