When interviews want to find out if you do have hands-on experience, they usually ask tools related questions. If you can explain what tools you have used to do what tasks, they assume you have the skills supported by the tools.
As for database design tools, there are many. The most popular ones are:
Rational Rose (from IBM)
ERWin (from CA)
Oracle Designer (from Oracle)
PowerDesigner (from Sybase)
A typical answer could be:
“I mainly used ERWin for database design in my previous projects. I used this tool to collect business entity data and did data modeling with entity relationship diagram, and then I used the tool’s function to build the logical database based on the ERD. I also use it to help me in physical database design analysis and generate SQL scripts to build database objects such as tables, indexes, and views. I’ve used ERWin for 4 years in Oracle and DB2 database design projects. But when I worked on Microsoft SQL Server, I used the build-in Enterprise Manager to do data modeling and create ERD.”
I think this is pretty good information for beginners