> For the complete documentation index, see [llms.txt](https://guvidocs.gitbook.io/guvi-mern/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://guvidocs.gitbook.io/guvi-mern/docs/module-7-database/mongodb/basic-crud-with-command-line.md).

# Basic CRUD with Command Line

MongoDB is a popular NoSQL database known for its flexibility and scalability. Performing CRUD (Create, Read, Update, Delete) operations is fundamental when working with databases. This blog post will guide you through the basic CRUD operations using the MongoDB command line interface.

**Prerequisites**

* MongoDB installed on your machine.
* MongoDB service running.
* Basic understanding of command line operations.

#### 1. Setting Up MongoDB

Before we start with CRUD operations, ensure MongoDB is installed and running on your system. To start the MongoDB server, run:

```bash
mongod
```

Open another terminal window and connect to the MongoDB shell:

```bash
mongo
```

#### 2. Creating a Database

MongoDB uses the concept of databases and collections. To create a database, simply switch to it using the `use` command. If the database does not exist, MongoDB will create it for you when you insert a document.

```bash
use myDatabase
```

Output:

```
switched to db myDatabase
```

#### 3. Creating a Collection

A collection in MongoDB is equivalent to a table in relational databases. To create a collection, you can use the `db.createCollection()` method or insert a document directly, which will create the collection if it doesn’t exist.

```bash
db.createCollection("myCollection")
```

Output:

```
{ "ok" : 1 }
```

#### 4. CRUD Operations

**Create**

To insert documents into a collection, use the `insertOne()` or `insertMany()` methods.

**Insert One Document:**

```bash
db.myCollection.insertOne({ name: "Alice", age: 25, city: "New York" })
```

Output:

```
{
    "acknowledged" : true,
    "insertedId" : ObjectId("...")
}
```

**Insert Multiple Documents:**

```bash
db.myCollection.insertMany([
    { name: "Bob", age: 30, city: "San Francisco" },
    { name: "Charlie", age: 35, city: "Los Angeles" }
])
```

Output:

```
{
    "acknowledged" : true,
    "insertedIds" : [
        ObjectId("..."),
        ObjectId("...")
    ]
}
```

**Read**

To retrieve documents from a collection, use the `find()` method.

**Find All Documents:**

```bash
db.myCollection.find()
```

Output:

```
{ "_id" : ObjectId("..."), "name" : "Alice", "age" : 25, "city" : "New York" }
{ "_id" : ObjectId("..."), "name" : "Bob", "age" : 30, "city" : "San Francisco" }
{ "_id" : ObjectId("..."), "name" : "Charlie", "age" : 35, "city" : "Los Angeles" }
```

**Find with Query:**

```bash
db.myCollection.find({ age: { $gt: 30 } })
```

Output:

```
{ "_id" : ObjectId("..."), "name" : "Charlie", "age" : 35, "city" : "Los Angeles" }
```

**Update**

To modify documents in a collection, use the `updateOne()` or `updateMany()` methods.

**Update One Document:**

```bash
db.myCollection.updateOne(
    { name: "Alice" },
    { $set: { age: 26 } }
)
```

Output:

```
{ "acknowledged" : true, "matchedCount" : 1, "modifiedCount" : 1 }
```

**Update Multiple Documents:**

```bash
db.myCollection.updateMany(
    { city: "Los Angeles" },
    { $set: { city: "LA" } }
)
```

Output:

```
{ "acknowledged" : true, "matchedCount" : 1, "modifiedCount" : 1 }
```

**Delete**

To remove documents from a collection, use the `deleteOne()` or `deleteMany()` methods.

**Delete One Document:**

```bash
db.myCollection.deleteOne({ name: "Bob" })
```

Output:

```
{ "acknowledged" : true, "deletedCount" : 1 }
```

**Delete Multiple Documents:**

```bash
db.myCollection.deleteMany({ age: { $lt: 30 } })
```

Output:

```
{ "acknowledged" : true, "deletedCount" : 1 }
```

#### 5. Conclusion

Using the MongoDB command line interface, you can easily perform basic CRUD operations. This guide covered creating a database and collection, as well as how to insert, read, update, and delete documents. These fundamental operations form the backbone of working with MongoDB, enabling you to manage and manipulate your data efficiently.

For more advanced operations and configurations, refer to the [MongoDB Documentation](https://docs.mongodb.com/).