如何从猫鼬的数组中删除嵌套对象

Question

This is my first web application and I need to delete a nested array item. How would you delete an object in Mongoose with this schema:

User: {
    event: [{_id:12345, title: "this"},{_id:12346, title:"that"}]
}

How can I go about deleting id:12346 in mongoose/Mongo?

Answer 1

Use $pull to remove items from an array of items like below :

db.User.update(
  { },
  { $pull: { event: { _id: 12346 } } }
)

The $pull operator removes from an existing array all instances of a value or values that match a specified condition.

Empty object in the first parameter is the query to find the documents. The above method removes the items with _id: 12345 in the event array in all the documents in the collection. If there are multiple items in the array that would match the condition, set multi option to true as shown below :

db.User.update(
  { },
  { $pull: { event: { _id: 12346 } } },
  { multi: true}
)

Answer 2

Findone will search for id,if not found then err otherwise remove will work.

   User.findOne({id:12346}, function (err, User) {
        if (err) {
            return;
        }
        User.remove(function (err) {
            // if no error, your model is removed
        });
    });