biblatex: Only show doi or ISSN or ISBN

Question

Im looking for a way to only show one of ISBN, ISSN or doi. It should prefer doi over ISSN over ISBN. My current approach as listed below is doing nothing, which gets me confused. Any help around?

Cheers

\renewbibmacro*{issn}{% 
    \iftoggle{bbx:doi} {\iffieldundef{doi}{\usebibmacro{issn}}{}} {}
}

Answer 1

A simple solution that should work almost universally is

\AtEveryBibitem{%
  \iffieldundef{doi}
    {\iffieldundef{issn}
       {}
       {\clearfield{isbn}}}
    {\clearfield{issn}%
     \clearfield{isbn}}%
}

For the standard styles the shorter

\AtEveryBibitem{%
  \iffieldundef{doi}
    {}
    {\clearfield{issn}%
     \clearfield{isbn}}%
}

should be enough since no entry shows both ISBN and ISSN - it is either or.

You can do the same thing with Biber's sourcemapping which stops the data from even reaching biblatex (this is usually preferred with data that could be used for things other than being printed directly - for example dates and names that could be used for sorting or label... fields).

\DeclareSourcemap{
  \maps[datatype=bibtex]{
    \map{
      \step[fieldsource=doi, final]
      \step[fieldset=isbn, null]
      \step[fieldset=issn, null]
    }
  }
}