Depends, dynamodb is just basically a fancy serverless key-value store (with possibility to add secondary indexes and what not). If your app knows the primary key of the things it needs to fetch. Then I'm sure dynamodb would be a good fit. If you need to scan for data, then perhaps not. More on reddit.com

The main thing is SQL vs NoSQL. SQL require you to structure your data, NoSQL doesnt. Doesnt have to structure your data sounds nice, until you realize that most application have structured (and relational) data. It's like throwing all your cloths, towels, socks,... in a pile instead of neatly place them in different compartments of your wardrobe. Easy and quick, but hard to manage. To be fair, NoSQL had their use, but most of the time it isnt what you want. If you have structured and relational data, you will end up checking for the structure of data before insert to NoSQL database anyway. So, my advice is, always go for SQL, unless you have reeeeeeally good reason not to. As for, what specific SQL? Postgres, Mysql, OracleDb, MSSQL,...? Doesn't matter, they do have exclusive feature, but you wont need them 99% of the time More on reddit.com

Relational databases should be your first choice always, until performance dictates otherwise. All the NOSQL database make sacrifices in order to get higher speed. If you've ever used Cassandra, you'll know that write speeds are extremely fast, but the query is extremely specific. You can't do random queries on Cassandra, they'll usually timeout unless it's a subquery of a supported query. It's also great for sharding large amounts of data. So it works better than relational databases for very specific circumstances. Same goes for MongoDB or Redis that requires all data to be in memory. You may very well need to make these sacrifices in order to get the performance or scaling that you need. But you should always start with RDB because it will handle everything up until you get to the size when you need to switch strategies to a NOSQL. More on reddit.com

Redis is a cache, not a database. Caches are easy to deal with, other than the whole "when do I invalidate stuff" part. I realize people sometimes use it as a database. But people also drink bleach as an anti-viral. More on reddit.com