How to Remove a Specific Object from an Array in MongoDB?

MongoDB: Removing an Object from an Array

Problem:

In MongoDB, how do you extract a specific object from an array embedded within a document? In the example document, we want to remove the object with id: 23 from the items array.

Solution:

To achieve this, use the $pull operator with a more specific query to match the desired object within the array.

MongoDB Query:

db.mycollection.update(
    { '_id': ObjectId("5150a1199fac0e6910000002") }, 
    { $pull: { items: { id: 23 } } },
    false, // Upsert
    true // Multi
);

Explanation:

• $pull operator: Used to remove an element from an array.
• { items: { id: 23 } }: Specify the nested object to remove by matching its specific field.
• Upsert: Set to false to prevent creating a new document if the update doesn't match any existing document.
• Multi: Set to true to apply the update to multiple matching documents (although there should only be one match in this case).

Node.js/Mongoose:

In Mongoose, you can use the following query:

<code class="javascript">MyModel.findOneAndUpdate(
  { '_id': '5150a1199fac0e6910000002' },
  { $pull: { items: { id: 23 } } },
  { multi: true }
);</code>

Note: MongoDB 3.6 also supports the $elemMatch operator in conjunction with $pull for more complex filtering within arrays.

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