How to connect alfresco database? and Where the user details are stored in alfresco database? How we can view all the user details from the database? If possible to add any new field in alfresco tables?
As Kalpesh Patel said, is not a good option modify Alfresco's tables. Anyway, if you want to take a look at the Alfresco's data model, maybe you can download DBVisualizer or any other software tool to view tables (just only as a learning purpose).