MongoDB Basics

Atlas

• Replica Set - a few connected machines that store the same data to ensure that if something happens to one of the machines the data will remain intact. Comes from the word replicate - to copy something.

• Instance - a single machine locally or in the cloud, running a certain software, in our case it is the MongoDB database.

• Cluster - group of servers that store your data.

BSON

JSON and BSON | MongoDB

BSON (Binary JSON) Serialization

Import & Export

SRV connection string - a specific format used to establish a connection between your application and a MongoDB instance

# JSON
mongoimport --uri="mongodb+srv://<your username>:<your password>@<your cluster>.mongodb.net/sample_supplies" --drop sales.json

mongoexport --uri="mongodb+srv://<your username>:<your password>@<your cluster>.mongodb.net/sample_supplies" --collection=sales --out=sales.json

# BSON
mongorestore --uri "mongodb+srv://<your username>:<your password>@<your cluster>.mongodb.net/sample_supplies"  --drop dump

mongodump --uri "mongodb+srv://<your username>:<your password>@<your cluster>.mongodb.net/sample_supplies"

mongo Shell

show dbs

use <db_name>

show collections

it // iterates through a cursor

• cursor: A pointer to a result set of a query
• pointer: A direct address of the memory location

CRUD

Create

insert()

db.<collection_name>.insert({"field": "value"})

Delete

deleteOne()

deleteMany()

drop()

Update

Update Operators — MongoDB Manual

updateOne()

updateMany()

Read

find()

db.<collection_name>.find({field: "value"}).count()

db.<collection_name>.find({field1: "value1", field2: "value2"})

db.<collection_name>.find({field1: "value1", field2: "value2"}).pretty()

findOne()

db.<collection_name>.findOne();

Query Operators

Comparison

Logic

Expressive

Array