The standard technical answer:

It depends.

Having said that, if we're talking standard SQL (so that the SQL is portable across all of the db's), then it's basically possible. If you start getting into db-specific stuff (which is *really* hard NOT to do), you'll have problems.

As for handling the connection to different db's....that's fairly straightforward, assuming this "admin console" of yours allows that type of thing. The problem is how that works....since you have to know db-specific things to connect to the db.

JDBC provides meta-data about the queries, so when you enter your sql, you can know the column types, etc. However, beware. Not all db's handle it the same, or are all drivers created equal.

In theory, it's possible. In practice, you'll probably run into many gotcha's.

Dan