I rarely use SQL Server 2008 at ordinary times, and occasionally use it once. I have encountered some problems. After several twists and turns, I found a solution on the official website:
Problem description: After logging on to the database, click "Database". The server subject "xxxcom" cannot access the database "db_xxx_com" in the current security context ".
Cause: SQL Server 2008 bug
Solution (non-original, refer to the official website ):
1. log on to the server using SQL Server Management studio.
2. In the object Resource Manager, click the database folder.
3. Right-click the column title in "Object Resource Manager Details" and click "Reset View ". If the "Object Resource Manager Details" page is not visible, click "Object Resource Manager Details" on the "View" menu ".
4. In object Resource Manager, right-click the database folder and click Refresh ".
5. Click the database folder.
6. Right-click the column title of "Object explorer details" and click to clear the "sorting rules" check box.
7. In object Resource Manager, right-click the database folder and click Refresh ".
In this case, OK.
I have passed the test.