If it makes sense for your model

@@@ Python
class User()
    string Name
    List<string> Addresses
    List<string> PhoneNums
    List<Order> Orders

class Order()
    int Price
    List<Widget> Items

!SLIDE

Relational model starts to get bloated

@@@ Sql
tblUsers
    -tblUserAddresses
    -tblUserPhoneNums
    -tblUserOrders
tblOrders
    -tblOrderItems # Join, Join, Join ...

!SLIDE @@@ Json { “name”:”matt”, “addresses”: [ “123 Main St”, “4 Center Green” ], …

    "orders": [
        {
            "name": "Learn MongoDB",
            "price": 30
        },
        {
            "name": "Widget #7",
            "price": 77
        }
    ]
}

!SLIDE @@@ db.Users.find( {“orders.name” : “Learn MongoDB”} )

vs

select * from tblUsers U
join tblUserOrders UO
on UO.UserId = U.oid
join tblOrders O
on O.oid = UO.OrderId
where O.Name = "Learn MongoDB"

!SLIDE bullets

Real-time Analytics

Upset + $inc
Fire and forget
Write heavy
Flexible reporting

!SLIDE center