In our discussion of NoSQL types and databases, we will primarily focus on the following characteristics of NoSQL databases:
- In-memory databases
- Columnar databases
- Document-oriented databases
- Key-value databases
- Graph databases
- Other NoSQL types and summary
Most types of NoSQL used in the industry today fall into one or more of these categories. The next few sections will discuss the high-level properties of each of these NoSQL offerings, their main advantages, and products in the market that fall into the respective categories.
In-memory databases, as the name implies, leverage the computer memory; that is, the RAM, to store datasets. Before we look into how in-memory databases work, it would be worthwhile to recollect how data transfer happens in a typical computer:
Simple Data Flow Computer Hierarchy
As shown in the preceding image, data traverses from disk to memory to the CPU. This is a very high-level generalization of the exact process as there are conditions...
