A schema means different things for an SQL and a NOSQL database management system. If you are using SQL, you have to tell the system about the format of the data before you can use – that is the schema. When it comes to NOSQL databases everything is different. You don’t need a schema, you simply present data and the system stores it in whatever format you send it.
Each document in a collection1 can be a different layout and different types of data. The flexibility of NOSQL databases suggests that data design is less important. For example I read: “… since NoSQL doesn’t necessitate the need for a schema, you avoid the expense and time of that initial design stage.”
I don’t think so
(more…)
Bob Browning's blog 