Most frequently asked DynamoDB Interview Questions

1. What is DynamoDB?
2. What are advantages of DynamoDB?
3. What are Indexes and Secondary Indexes in DynamoDB?
4. What is Partition Key?
5. How to perform replication between applications by using Amazon DynamoDB?
6. Does DynamoDB support SQL?
7. What are the difference between Amazon DynamoDB and Amazon SimpleDB?
8. Data Types supported by DynamoDB?
9. Two types of primary key used by DynamoDB?
10. What does Data Pipeline do?
11. What are Projections in DynamoDB?

What is DynamoDB?

DynamoDB is a NoSQL database service which is designed to deliver fast performances.It supports key-value and document data structures and allows users to create tables for our database for storing and retrieving any data volume and supporting all traffic levels.

What are advantages of DynamoDB?

• Scalable - unlimited storage for data
• Cost Effective - it charges for reading, writing, and storing data along with any optional features
• Data Replication - helps to manage replication across multiple availibility zones
• Secure - Advanced System of Notification and Reporting
• Easy Administration - it has fully managed services

What are Indexes and Secondary Indexes in DynamoDB?

Indexes is used to improve accesses for primary key attributes.
Secondary indexes are used for holding attribute subset and an alternate key.
There are two types of secondary indexes:
Global Secondary Index
Local Secondary Index

What is Partition Key?

Primary key is used to input an internal hash function.the output from the hash function will determine the partition and where i will be stored.

How to perform replication between applications by using Amazon DynamoDB?

Does DynamoDB support SQL?

Yes, as SQL helps in storing and retrieving data.

What are the difference between Amazon DynamoDB and Amazon SimpleDB?

Amazon DynamoDB
Fast and scalable
Helps to maintain predictably high performance and to be highly cost-effective for workloads
Amazon SimpleDB
Scaling limitations
It attribute and support flexibility at the cost of performance

Data Types supported by DynamoDB?

Data Types supported by DynamoDB are :
Number Set
String Set
Binary Set
Heterogeneous List
Heterogeneous Map

Two types of primary key used by DynamoDB?

Partition Key - Used for hash value to determine storage.
Sort Key - Used to determine storage location.

What does Data Pipeline do?

Data Pipeline exports and imports data from S3 bucket, file, etc.It also helps in backups, testing, and for similar needs.
There are 2 types Data Pipeline:
DataPipelineDefaultRole - contains all the ations you permit the pipeline to perform.
DataPipelineDefaultResourceRole - contains all the resources you permit the pipeline to perform.

What are Projections in DynamoDB?

They are a set of attributes which are copied from the table to an index.Projection will always occur with the table partition key and sort key.
Each index contains minimum 3 attributes:
Table partition key value
Attribute to serve as the index sort key
Table sort key value