Database categories

Many database models have appeared and vanished, such as the network model and the hierarchical model. The predominant categories now in the market are relational, object-relational, and NoSQL databases. One should not think of NoSQL and SQL databases as rivals; they are complementary to each other. By utilizing different database systems, one can overcome many limitations and get the best of different technologies.

NoSQL databases can provide great benefits such as availability, schema-free, and horizontal scaling, but they also have limitations such as performance, data retrieval constraints, and learning time. Relational databases often adhere to SQL as defined by ISO. SQL is a very expressive and extremely powerful tool for retrieving data in different forms. Many NoSQL databases such as Cassandra lack the capability to retrieve data as in relational databases.