There are no schemas anywhere in sight of SimpleDB. You don't have to create schemas, change schemas, migrate schemas to a new version, or maintain schemas. This is yet another thing that is difficult for some people from a traditional relational database world to grasp, but this flexibility is one of the keys to the power of scaling offered by SimpleDB. You can store any attribute-value data you like in any way you want. If the requirements for your application should suddenly change and you need to start storing data on a customer's Twitter handle for instance, all you need to do is store the data without worrying about any schema changes!
Let's add an e-mail address to the database in the previous example. In the relational database, it is necessary to either add e-mail to the phone table with a type of contact field or add another field. Let's add another table named Email_Info.
Person_Info table:
|
ID |
First_Name |
Last_Name |
|---|---|---|
|
101 |
John |
Smith |
|
102 |
Bill |
Jones |
Phone_Info table...