What is DynamoDB and how it works?

Question: I'm currently using MongoDB on-premises and reviewing alternative options for storing NoSQL data. Our usage of MongoDB is very limited from a development pov , and looking for a much lighter weight NoSQL setup. What is DynamoDB and how does it work?

Answer:  DynamoDB is a managed NOSQL Service offered by AWS. The AWS documentation is very comprehensive   and should be referenced for detailed information .    Tables , Items & Attributes are essential concepts . 

A table is a collection of items 

Every item is a collection of attributes. 

Primary keys are used as unique identifiers 

Secondary Indexes are used to enhance queries

DynamoDB streams can be used  for data modification Events

To create a DynamoDB table you can use different interfaces , either through the AWS Console or Terraform 

Open the DynamoDB console at https://console.aws.amazon.com/dynamodb/.

Choose Create Table.

In the Create DynamoDB table screen, do the following:

On the Table name box, enter  "my table name"

For the Primary key, in the Partition key box, enter "my Id". Set the data type 

When the settings are as you want them, choose Create.

Once you have the DynamoDB table setup , need to think about the backup requirements - check out AWS Backup Service

The AWS Backup Service supports DynamoDB as one of the Resource types . 

To start adding items to DynamoDB ,  use either the DynamoDB API, or PartiQL , a SQL-compatible query language, to add an item to a table. There is a new feature in the AWS Console for DynamoDB called PartiQL Editor , allowing you to edit data in the DynamoDB table. Another option is to use the Console - where you can create an Item and attach attributes

If you want to use AWS CLI for creating a DynamoDB table , here is a sample to create a basic DynamoDB table .

aws dynamodb create-table \
    --table-name Cars \
    --attribute-definitions \
        AttributeName=Engine,AttributeType=S \
        AttributeName=Fuel,AttributeType=S \
    --key-schema \
        AttributeName=Engine,KeyType=HASH \
        AttributeName=Fule,KeyType=RANGE \
    --provisioned-throughput \
        ReadCapacityUnits=5,WriteCapacityUnits=5 \
    --table-class STANDARD

For  more aws cli commands use AWS CLI Cheatsheet