>What is different between Data Layer and Data Storage Layer?
>I'm not sure, I'm not understand you: what is Data Storage Layer ?

The Data Acess Layer would be in your code as a means to talk to the Data Storage Layer. This last one is the database. Could be Stored Procedures in SQL Server for example, or you could change to another database, using another language (like Oracle and PL/SQL) without affecting your program (other layers).

HTH