Databases

Question 1

Is S3 a database?

Answer 1

Yes. For big objects, backups, archives.

Question 2

What are Joins in databases and what kind of database is good for this feature?

Answer 2

A JOIN is a SQL instruction. used to query combined data from different tables by using values common to both tables.

If you need to use joins, you need a relational database.

Question 3

What are good databases for performing JOINS or online transactions?

Answer 3

SQL DBs: RDS, Aurora.

Question 4

What kind of database you need if you need a more flexible option to store data?

Answer 4

A no SQL database like DynamoDB.

Question 5

What are good options of databases for caching?

Answer 5

DAX to use with DynamoDB.
Elasticache for caching other databases, like RDS, etc.

Question 6

What are great databases for data warehouses?

Answer 6

Redshift, Athena, EMR.

Question 7

What database is great when database usage has sudden big spikes?

Answer 7

DynamoDB

Question 8

What database is great when you have rapidly evolving schemas?

Answer 8

DynamoDB

Question 9

What is a great database that can work as a serverless cache?

Answer 9

DynamoDB

Question 10

What is a great database for very big objects?

Answer 10

S3.

Question 11

How does AWS implement mongodb?

Answer 11

With DocumentDB

Question 12

What kind of db is mongodb?

Answer 12

noSQL.

AWS Managed similar to aurora. It doesn’t have a serverless option.

Question 13

What is a great database to store, query and index json data?

Answer 13

MongoDB

Question 14

How does documentdb work?

Answer 14

Very similar to aurora, but for mongodb.

Managed db.
HA across 3 AZ.
Auto scaling storage and throughput.

Question 15

What is a great database for graphs or charts?

Answer 15

Neptune.

Great for creating databases for interconnected data. Like for example a use case would be a social network.

Question 16

What are neptune streams?

Answer 16

A history of all changes made to your neptune graph, in order.

Useful to send notifications.
Stream data is accessible through rest api.

Question 17

Which AWS Services uses Apache Cassandra?

Answer 17

Amazon Keyspaces

Question 18

What is a great database for a ledger?

Answer 18

Amazon QLDB (Quantum ledger Database).

Question 19

What are the general characteristics of QLDB?

Answer 19

Its immutable.
For Ledgers.
Fully managed.
Serverless.
HA 3 AZ.

Question 20

Use cases pf QLDB?

Answer 20

To review the history of all changes made to your application data.

Question 21

What is a great service for storing time series data?

Answer 21

Amazon Timestream.

Time series is data that has a year related to it.

Question 22

What is the main advantage of using timestream instead of a relational database?

Answer 22

1000s times faster and 1/10th the cost of a relational database.

Handles time-stamped data better.

Question 23

Which database is redis compatible?

Answer 23

Elasticache

Question 24

You want to migrate an on-premises MongoDB NoSQL database to AWS. You don’t want to manage any database servers, so you want to use a managed NoSQL Serverless database, that provides you with high availability, durability, and reliability, and the capability to take your database global. Which database should you choose?

Amazon RDS
Amazon DynamoDB
Amazon DocumentDB
Amazon Aurora

Answer 24

Amazon DynamoDB

DocumentDB is not serverless.

Question 25

What is the best database for Online Transaction Processing (OLTP)?

Answer 25

Postgre. For aws its RDS or Aurora.