The library screen has a special feature to quickly change the capitalization of ALL the song titles. If your database has a mix of "ALL CAPS SONG TITLES" and "Mixed Case Song Titles", you can use the [Make all titles UPPERCASE] or [Make all titles Mixed Case] items from the [Database] submenu of the [File] menu.
When you confirm your request, the software will quickly adjust all the titles in the database accordingly.
Please note: the titles change is permanent; you cannot undo it.