Sql Server What Is The Advantage Of Installing SQL Server Express On A Virtual Machine?

What is the advantage of installing SQL Server Express on a Virtual Machine? - sql server

I'm in a SQL class in which we are using SQL Server Express 2005. In our teaching is on a computer "virtual installation". I thought the installation of SQL on my system for projects to do, but I'm worried that the consumption of system memory. Is that why some people can only work in the virtual machine?