A non-relational database that stores data as a simple key-value pair is called what?

A non-relational database that stores data as a simple key-value pair is called what?

• A. Key/value databases
• B. Document databases
• C. Relational databases
• D. Graph databases

Answer: (A)

Key-value databases store data as simple pairs: a unique key and its associated value. This makes lookups fast because you retrieve data by exact key, with no need to scan or join other structures. The value can be a primitive or a more complex object, but the retrieval method remains straightforward—give me the key, I return the value. This differs from document databases, which store structured documents (like JSON) and support queries over the document’s internal fields. Relational databases organize data into tables with a fixed schema and use SQL to query and join data. Graph databases model relationships as nodes and edges to navigate connections. Because the question describes a system that uses a single key to access its value, the described approach is the key-value store.

Key-value databases store data as simple pairs: a unique key and its associated value. This makes lookups fast because you retrieve data by exact key, with no need to scan or join other structures. The value can be a primitive or a more complex object, but the retrieval method remains straightforward—give me the key, I return the value.

This differs from document databases, which store structured documents (like JSON) and support queries over the document’s internal fields. Relational databases organize data into tables with a fixed schema and use SQL to query and join data. Graph databases model relationships as nodes and edges to navigate connections. Because the question describes a system that uses a single key to access its value, the described approach is the key-value store.