I received a set of data file, with .bak extension, and the non-technical guy told me that it's from MySQL database. Checking out how to import a SQL Server .bak file into MySQL and opening .mdf file , I suspect if it's really MYSQL, as there is one .mdf file in the list, which seems to me it's from SQL Server db.
My question is, (a) does MYSQL auto backup 4GB data file into .bak extension? (b) It's been 5yrs, is there new edition other than SQL Server 2008 Express, which I can use to try opening the .bak?