Welcome to the discussion about this lecture. Here you can ask questions or post feedback about this specific lecture.
A combination of different types of Data Bases can be used in combination in the same application or project.
e.g. SQL for your USERS who log into your website.
These users might deploy sensors on an environmental project - the sensors gather Gigabytes of data which is streamed into a NoSQL Database,
And then there could be a GRAPH database that can be used to view the more complex information about your users, the sensors they deploy and the information collected by the sensors.
Then, when the information collected from all three gets HUGE (!) you might need to add a search engine to access the information that is in the SQL, NoSQL and GRAPH databases, and also you might need to access your BLOCKCHAIN.
So be flexible and recognize that all types of databases can be used together.
This is much easier to do with Vertical Slice Arch. You might want to check it out if you’re not already familiar with it. https://jimmybogard.com/vertical-slice-architecture/