Which application should I use to create a relational database from an excel file? I have an excel inventory of network assets (inaccurately sold as a 'CMDB') that is becoming difficult to manage. I need to import the data into some kind of database but I dont know which one to use. It has to be easy to update - i.e add/modify/delete records and also be easy to show which records have been updated and when 

It would be really good if I could show relationships between items for example, one line showing a the record for a router and another line showing which LAN switches are connected to it.

thanks
Well if you know how to modify/insert/delete data by using some basic SQL queries and would like to have remote access to the database from other machine, then MS SQL Server can be a good choice. You can download the Express version here for free.