Gain insights into MongoDB's core concepts, including queries, CRUD operations, aggregation, and more. Discover how to build applications with hands-on experience and interactive widgets.

mongo.tar.gz

MongoDB is an open-source NoSQL database and stores data in the form of documents. It can be used as an alternative to traditional relational databases. NoSQL databases are schema-less and useful for working with large sets of distributed data. 

In this course, you will learn the core concepts of MongoDB including queries, documents, embedded documents, and operators with advanced features like CRUD operations, bulk write operations, GridFS, indexing, aggregation pipeline, authorization, and more.

You will have plenty of hands-on experience with the help of interactive widgets, and by the end you will have a strong understanding of how to build MongoDB-based applications.

MongoDB: The Complete Guide

# Bulk write operations

## `deleteOne`

The **`deleteOne`** operation is used to delete one document.

Syntax:

```
db.<collection-name>.bulkWrite([
   { 
       deleteOne : { 
           "filter" : <document>,
           "collation" : <document> 
        } 
    }
])
```
This function deletes the first document in the collection that matches the `"filter" :  <documents>`. 

Below is an example of how to perform delete operations on the `task` collection using `bulkWrite`.


db.tasks.bulkWrite([
{ 
  deleteOne : {
      filter : {
          name: "Task 1"
      },
  }
}
])

This query returns the below output.

```
{
  acknowledged: true,
  insertedCount: 0,
  insertedIds: {},
  matchedCount: 0,
  modifiedCount: 0,
  **deletedCount: 1,**
  upsertedCount: 0,
  upsertedIds: {}
}
```

Here, the `deleteCount:1` means that `deleteOne` has deleted one document from the collection.

Even if the `filter query` returns more than one document, this operation will delete the first one only.

Similar to other operations, `deleteOne` can be used multiple times in `bulkWrite`.

Learn and practice bulk write queries for the deleteOne, deleteMany, replaceOne operations.

Introduction to Database and MongoDB

Create Database and Authorization

Performing CRUD Operations on MongoDB - Part 1

Performing CRUD Operations on MongoDB - Part 2

MongoDB Query and Database Performance

Learn Additional MongoDB Topics

Appendix

Bulk Write: Part 2

Bulk write operations

`deleteOne`