Hi,
I might misunderstand you but I don't really get what you did. By "MySQL settings" you mean you changed the default collation in the configuration file? If so it would not have the mentioned effect that your database is empty suddenly.
It rather sounds to me as if you look at the wrong server or schema now. When you change the charset of an object (say a schema or a table) it may convert your text to that new encoding, depending on what is set for individual sub elements like columns, but it will certainly not wipe out your database. So, I'd say there is something else involved here, not just changing.
And finally, there is no single command in MySQL which would allow to remove all data in one go. You will have to drop elements with several commands (like DROP table, DROP procedure, DROP schema etc.).
Mike Lischke, MySQL Developer Tools
Oracle Corporation
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