title: Key Value Store in NoSQL Database Systems
body: <p>Actually, whenever I search for key-value store used in some NoSQL database systems, I encounter the definition like this: "Each value has its own unique key and values are stored depending on their keys."</p>
  
  <p>However, I cannot understand substructure of this database system. </p>
  
  <p>Can we say that key-value store is a hash map in c++, and can the values be primitive types or objects?</p>