Meaning of 'show variables LIKE '%_database'
Show Variables is not ANSI SQL, it's MySQL specific, so it won't run across database providers.

Reading through that code it looks like it's trying to determine if the database provider will support UTF8.

If you Google it, the Show Variables is a MySQL command which returns information about the current database.

I think you will have to replace this whole section with different code to determine if the database in use will support UTF8, which I suspect is dependent on the collation.

You can find this information in the sys. tables.

Googling MSSQL Server and UTF8 seems to indicate that MS don't explicitly support UTF8, however.

This is an answer to your question "what is show variables", not a solution to your problem "how can my application run a query to determine UTF8 support in the database?"

HTH