Any external css will be overridden by the inline ones in the page itself. So in real terms external/outer ones do not matter.
If I understood your original problem the inline style sheet was corrupting the effects of others. So the 'simple' solution is to intercept the db text before it gets passed back as a response and the browser can act upon it with what ever styles are in scope and either rip it out or stop it conflicting.
You want to stop the style sheet embedded in the database having an impact, you've either got to take it out or change it. That would be either within the database content itself, in the query that gets it, or just after it's got. Those are your only options.