# MongoDB

### MongoDB native

**To connect to database**

use the connect settings in mongodb atlas

**Starting local database server**

After installing, you can start the mongod by

```bash
sudo systemctl start mongod
```

if you receive an error : **Failed to start mongod.service: Unit mongod.service not found.**

**Run the following command first:**

```bash
sudo systemctl daemon-reload
```

**Verify that MongoDB has started successfully.**

```bash
sudo systemctl status mongod
```

**You can optionally ensure that MongoDB will start following a system reboot by issuing the following command:**

```bash
sudo systemctl enable mongod
```

**Stop MongoDB.**

As needed, you can stop the [`mongod`](https://docs.mongodb.com/manual/reference/program/mongod/#bin.mongod) process by issuing the following command:

```bash
sudo systemctl stop mongod
```

**Restart MongoDB.**

You can restart the [`mongod`](https://docs.mongodb.com/manual/reference/program/mongod/#bin.mongod) process by issuing the following command:

```bash
sudo systemctl restart mongod
```

### MongoDB setup Docker

```bash
sudo docker run --name mongo --network mongonet -d \
 -p 27017:27017 \
 -e MONGO_INITDB_ROOT_USERNAME=admin \
 -e MONGO_INITDB_ROOT_PASSWORD=pass  \
 mongo

sudo docker exec -it some-mongo sh
```

**Begin using MongoDB.**

Start a [`mongo`](https://docs.mongodb.com/manual/reference/program/mongo/#bin.mongo) shell on the same host machine as the [`mongod`](https://docs.mongodb.com/manual/reference/program/mongod/#bin.mongod). You can run the [`mongo`](https://docs.mongodb.com/manual/reference/program/mongo/#bin.mongo) shell without any command-line options to connect to a [`mongod`](https://docs.mongodb.com/manual/reference/program/mongod/#bin.mongod) that is running on your localhost with default port 27017:

```bash
mongo "mongodb+srv://<username>:<password>@<url>:<port>/<db>"
```

**To show collections**

```bash
show dbs
use <name of db>

show collections
```

### Basic Commands

* List all databases : `show dbs`
* to switch to db : `use <name_of_db>`
* to run a query : `db.<name_of_collection>.[function name]`
* to iterate over many results : `it`
* add : `.pretty()` to see json better
* to find any one document from collection, just use `.findOne()`
* to create new collection : `db.createCollection("employees")`

To shutdown db server

```bash
use admin
db.shutdownServer()
exit
```

### To delete

```bash
drop collection
db.inspection.drop()
```


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