# <center><i class="fa fa-edit"></i> Navigating MongoDB: Importing, Exporting, and Querying Data </center>
###### tags: `Internship`
:::info
**Goal:**
To gain a basic understanding of MongoDB fundamentals. Focus on importing, exporting, and querying Data
- [x] Importing
- [x] Exporting
- [x] Querying Data

**Resources:**
[MongoDB Basics Online Course](https://university.mongodb.com/courses/M001/about)
[MongoDB 常用Query指令](/b2Y7lgR1RaeQyMHp9RGHdQ)
[Database Commands](https://www.mongodb.com/docs/manual/reference/command/)
:::
## Overview
- JSON: Javascript Standard Object Notation
- Pros
- User friendly
- Readable
- Familiar
- Cons
- Text-based -> slow
- Space consuming
- Supports limited number of basic data types
- JSON fomart in MongoDB
- Start and end with curly braces
- Separate key/field and values with a semicolon
- Separate each key:value pair with a comma
- Keys/fields must be surrounded by " " or ' '
- BSON: Bridges the gap between binary representation and JSON format
- Optimized for
- Speed
- Space
- Flexibility
- High performance
- General purpose focus


### Importing and Exporting Data
- URI String: Uniform Resource Identifier
- srv: Establishes a secure connection
- JSON
- mongoimport
> `mongoimport --uri="mongodb+srv://<your username>:<your password>@<your cluster>.mongodb.net/sample_supplies" --drop sales.json`
- mongoexport
> `mongoexport --uri="mongodb+srv://<your username>:<your password>@<your cluster>.mongodb.net/sample_supplies" --collection=sales --out=sales.json`
- BSON
- mongorestore
> `mongorestore --uri "mongodb+srv://<your username>:<your password>@<your cluster>.mongodb.net/sample_supplies" --drop dump`
- mongodump
> `mongodump --uri "mongodb+srv://<your username>:<your password>@<your cluster>.mongodb.net/sample_supplies"`

### Querying
- Data Explorer: Querying method from MongoDB directly
- Go to MongoDB cloud -> Clusters -> Collections
- Namespace: The concatenation of the database name and collection name is called a namespace.

:::warning
Looked at the `sample_training.zips` collection and issued the following queries by filtering:

{"state": "NY"}
{"state": "NY", "city": "ALBANY"}

:::
- Find Command: Querying method from the shell

**Procedures**
- Connect to Atlas Cluster

mongo "mongodb+srv://<username>:<password>@<cluster>.mongodb.net/admin"

- Show list of databases in the cluster

show dbs

- Select database of choice

use sample_training

- View collections in database

show collectioins

- To query the zips collection (issue `find()`)

db.zips.find({"state": "NY"})

- Iterate through the cursor

it

- `count()`

db.zips.find({"state": "NY"}).count()

- `pretty()`
- Places each field:value pair on a separate line

db.zips.find({"state": "NY", "city": "ALBANY"}).pretty()

- Find commant without a query presents first 20 documents in databse
- Not in any particular order

db.zips.find{}