Amazon DynamoDB is a fully managed, serverless, NoSQL database service. What does that mean? Well, let's break this definition down into parts. 

By "fully managed," we mean that the DynamoDB service is responsible for provisioning and maintaining the underlying infrastructure. There's no database administration required on your end, no servers to provision or retire, no operating system and database patching, no sharding, no replication, and no backup complexity. All of this is handled for you by AWS. 

Similarly, what we mean by the phrase “serverless” is that all server and server administration is completely invisible to the user. There are still servers that run DynamoDB behind the scenes, but they are not your responsibility. AWS takes care of them. All you are responsible for is your data and how you model that data. 

To model your data effectively, it helps to understand the type of database you’re using. DynamoDB is a NoSQL database. NoSQL databases, aka “not-only SQL” databases, store data differently than relational databases, depending on their data model. The most common NoSQL data models are key-value, document, graph, and wide-column databases. Amazon DynamoDB is most commonly used as a key-value database, although it does support document access patterns as well.

So what is a key-value database? 

Well, it’s a collection of key-value pairs, where the key is a unique identifier for the particular item or record. You access your data based on these keys. Generally, to provide quick access to data, these key-value stores need to be highly partitionable and scalable. Two things which DynamoDB excels at. 

That’s it for this one - see you in the next one.