Different Databases for Ax 2012 in Sql Server

Databases include the Microsoft Dynamics AX DataBase, Model, and the Baseline database.

1. The AOS connects to the Microsoft Dynamics AX database to process transactions. 
2. The AOS connects to the model store to display application elements such as forms and reports.
3. The baseline database contains a model store that is used to upgrade X++ code to Microsoft Dynamics AX 2012. The baseline database is used to analyze application updates before they are applied.
Other Microsoft Dynamics AX components, such as Enterprise Portal and Reporting Services extensions, also include databases. The additional databases are created when you install those components and their prerequisites.