DynamoDB – Introduction

 DynamoDB allows users to create databases capable of storing and retrieving any amount of data and comes in handy while serving any amount of traffic. It dynamically manages each customer’s requests and provides high performance by automatically distributing data and traffic over servers. It is a fully managed NoSQL database service that is fast, predictable in terms of performance, and seamlessly scalable. It relieves the user from the administrative burdens of operating and scaling a distributed database as the user doesn’t have to worry about hardware provisioning, patching Softwares, or cluster scaling. It also eliminates the operational burden and complexity involved in protecting sensitive data by providing encryption at REST. 

DynamoDB Vs RDBMS

The below table provides us with core differences between a conventional relational database management system and AWS DynamoDB: 

Operations	DynamoDB	RDBMS
Source connection	It uses HTTP requests and API operations.	It uses a persistent connection and SQL commands.
Create Table	It mainly requires the Primary key and no schema on the creation and can have various data sources.	It requires a well-defined table for its operations.
Getting Table Information	Only Primary keys are revealed.	All data inside the table is accessible.
Loading Table Data	In tables, it uses items made of attributes.	It uses rows made of columns.
Reading Table Data	It uses GetItem, Query, and Scan	It uses SELECT statements and filtering statements.
Managing Indexes	It uses a secondary index to achieve the same function. It requires specifications (partition key and sort key).	Standard Indexes created by SQL is used.
Modifying Table Data	It uses a UpdateItem operation.	It uses an UPDATE statement.
Deleting Table Data	It uses a DeleteItem operation.	It uses a DELETE statement.
Deleting Table	It uses a DeleteTable operation.	It uses a DROP TABLE statement.

Advantage of DynamoDB:

The main advantages of opting for Dynamodb are listed below: 

• It has fast and predictable performance.
• It is highly scalable.
• It offloads the administrative burden operation and scaling.
• It offers encryption at REST for data protection.
• Its scalability is highly flexible.
• AWS Management Console can be used to monitor resource utilization and performance metrics.
• It provides on-demand backups.
• It enables point-in-time recovery for your Amazon DynamoDB tables. Point-in-time recovery helps protect your tables from accidental write or delete operations. With point-in-time recovery, you can restore that table to any point in time during the last 35 days.
• It can be highly automated. 
   

Limitations of DynamoDB –

The below list provides us with the limitations of Amazon DynamoDB: 

• It has a low read capacity unit of 4kB per second and a write capacity unit of 1KB per second.
• All tables and global secondary indexes must have a minimum of one read and one write capacity unit.
• Table sizes have no limits, but accounts have a 256 table limit unless you request a higher cap.
• Only Five local and twenty global secondary (default quota) indexes per table are permitted.
• DynamoDB does not prevent the use of reserved words as names.
• Partition key length and value minimum length sits at 1 byte, and maximum at 2048 bytes, however, DynamoDB places no limit on values.