Before venturing deeper into Firebase, let's first explain why we are talking about lists in the first place. In a relational database, we would be using SQL, tables, and normal forms to define our database. This is not the case with a Firebase database, as it is made of a JSON structure, looking something like this:

{
  "person": {
    "age": 11,
    "name": "Charlie",
    "address": "First Street, Little Town"
  },
  "orders": {
    "someKeyHash": {
    "orderDate": "2010-01-01",
    "total": 114
  },
  "someOtherKeyHash": {
    "orderDate": "2010-02-28"
  }
}

Notice how the orders collection in a relational database would be an orders table with a lot of rows. Here, it seems to be an object; why is that?