It’s today a common statement to affirm that hegemony of monolithic relational database system is ending.
ORM, Object Relation Model, were the last trial to perpetuate that pattern born in the 70’s. ORM bring to software development specialist the sweet feeling of directly interacting with objects. In Ruby on Rails world, Active Record was a wonderful implementation imposing its conventional relational approach on all web developer. In “Java world”, Hibernate has still a massive user base but controversy about its performance and ability to handle some complex situation are numerous.
Long story made short, Relational Databases persist data. That’s a fact as for all storage systems but they also structure the way we represent and organize our data model. They oblige us to think them through principles such as cardinality, relation entity, foreign keys and all those typical normalized form concept Entity Relationship Model. Furthermore, well know performance might quickly be an issue when mixing ORM and relational Databases. You want to make a query with 15 joins to display a deeply structured data set with few conditions and limit? You should rethink it.