Recommended DB solution for iOS POS app

Question

Hi,

I have created a large POS app that is heavily intergrated with SAP. Now I've started decouple it from SAP and use AWS as backend instead. (I'm rookie in AWS) 
My initial idea was to use Amplify and DynamoDB, even though I'm a lot more familiar with relational DB's like SAP HANA and SQL. 
The table setup might look something like this;
**Master data:**
Product Groups: 100 entries
Products: ~50k entries
Prices: 5-10m entries
Customers: 500k entries (with supporting tables like CustomerOrders, CustomerShipToParties, CustomerContacts etc)
**Transactions**
Receipts with separate tables for header, items, payments. "Joined" with unique transaction UUID or similar.

Multiple iOS devices accross stores will download masterdata and create receipts in backend. Once persisted, they will be exported from AWS to external ERP system (e.g SAP) and external ERP transaction ID's will be persisted in AWS DB.

Based on the above - are DynamoDB a viable/recommended solution or should an RDS be utilized instead?

Thanks in advance!

Answer

Hello.  
DynamoDB is NoSQL, so it is often faster to read and write than RDS.  
However, it has the disadvantage of not being able to throw as complex queries as an RDBMS.  
If you do not need to perform difficult queries, you can choose DynamoDB.  
If you are specializing in searching by joining tables, etc., you should use RDS.

You may want to evaluate which database your application is better suited for by looking at the comparison chart in the following document.  
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/SQLtoNoSQL.WhyDynamoDB.html

Recommended DB solution for iOS POS app

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