Relational vs. Non-Relational DBs

The big difference between relational and non-relational databases is that non-relational databases tend to nest their data. Instead of always keeping records in separate tables, they often store records within other records.

To over-simplify it, you can think of non-relational databases as giant JSON blobs. If a user can have multiple courses, you might just add all the courses to the user record.

{
  "users": [
    {
      "id": 0,
      "name": "Elon",
      "courses": [
        {
          "name": "Biology",
          "id": 0
        }
      ]
    },
    {
      "id": 1,
      "name": "Curly",
      "courses": [
        {
          "name": "Biology",
          "id": 0
        }
      ]
    }
  ]
}

This often results in duplicate data within the database. That's obviously less than ideal, but it does have some benefits that we'll talk about later in the course.