A key-value store is a data structure designed for storing and returning values associated with keys that act as unique identifiers. It’s often referred to as a “dictionary” or “hash table.'' \r\n Relational databases  \r\n A database back end for your application is vital. It’s likely your database is a relational database. This is because relational databases have dominated the software industry for decades, even as other technologies have radically changed around them.  \r\n In a relational database management system (RDBMS), data needs to be actively managed and maintained. An RDBMS categorizes data in the form of tables, and the database manager must create a blueprint — otherwise known as a schema — of the relationships between those tables before any data gets stored.…