multiple content database in SharePoint 2007 Site

Attaching Database in case there are multiple content database in SharePoint 2007 Site

If the SharePoint 2007 site contains multiple databases, then the order of attaching the content database is as follows:

1. The Content DB containing the root site collection is always applied first.
2. The other content DBs can be applied in any order.

Attach the Content DB To SharePoint 2010 Application

The process of attaching the content DBs in the SharePoint 2010 Web Application should be done through STSADM tool. For Attaching the Content DB to a SharePoint 2010 Web application, you should perform the tasks in the following order:

1. Restore the Content DBs to New SQL Server Instance
2. Delete the existing content DB of the Web application
3. Attach the Content DB of the Root Site collection

        Test-SPContentDatabase -Name -WebApplication [-AssignmentCollection ]
       [- DatabaseCredentials ] [-ServerInstance ]

      Mount-SPContentDatabase -Name <DatabaseName> -DatabaseServer <ServerName> -      WebApplication <URL> [-Updateuserexperience]

1. Attach the Content DB of other Site / Site Collections if any
2. perform an iisreset
3. Open the SharePoint 2010 Web Application
4. Perform the Visual upgrade to get the SharePoint 2010 Look and Feel

Upgrade MySite

To upgrade the MySite to SharePoint 2010, you should perform the following activities

1. Configure the My sites in SharePoint 2010
2. Perform the Content DB attachment method as discussed earlier.