fix: oracle cannot support DB in table identifiers

[imnotjames]

Description of change

oracle queries cannot support the identifier including the database in this way (XE.SYSTEM.table)

Instead, if you should specify a separate database a link must be set up and then
the database link identifier is included after the table. (SYSTEM.table@XE)

However, because that's rather difficult to set up lets not for now & just prevent
inclusion of the database in the case that we fetch it.

Pull-Request Checklist

• Code is up-to-date with the master branch
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• This pull request links relevant issues as Fixes #0000
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