Building Enterprise JavaScript Applications

Document vs. relationship data storage

For example, your application may be a school directory, storing information about schools, users (including teachers, staff, parents, and students), exams, classrooms, classes, and their relations with each other. Given that the data structure can be kept relatively flat (that is, mostly simple key-value entries), a relational database would be most suitable.

On the other hand, if you're building a social network, and want to store a user's settings, a document database may be more suitable. This is because the settings may be quite complex, such as the one shown here:

{  "profile": {    "firstName": "",    "lastName": "",    "avatar": "",    "cover": "",    "color": "#fedcab"  },  "active": true, "notifications": { ...