All the samples online show that Dapper.net works with SQL Server. What about other Databases like mySQl or Oracle? Is there a guideline or sample on how to do so?
Pretty much, no change. The only major difference is that the connection you are starting from will be of a different type, but since the extension method is on the base connection that won't matter. The command is of course for a different engine so the SQL variant may be slightly different, including using a different prefix for parameters
$bar etc. Dapper automatically detects oracle for enabling pass-by-name.