BibLaTeX – Adding Custom Field in BibLaTeX for Bibliographies

biberbiblatexbibliographies

I would like to allow for an optional custom field in my .bib entries. I do not need these fields to be part of the bibliography, but would like to be able to access these via

\citefield{<entry-key>}{<custom-field-name>}

The answer is probably somewhere in the references listed below, but my initial attempts to adapt \DeclareSourcemap and \DeclareFieldFormat failed.

References:

Code:

\begin{filecontents}{mybib.bib}
@book{knuth1984texbook,
  title={The texbook},
  author={Knuth, D.E. and Knuth, A.D. and Bibby, D. and American Mathematical Society and Addison-Wesley Publishing Company and Addison-Wesley},
  isbn={9780201134483},
  lccn={85030845},
  series={Computers \& typesetting},
  url={https://books.google.com/books?id=hEYuAQAAIAAJ},
  year={1984},
  publisher={Addison-Wesley},
  myFieldA={Useful Book},
  myFieldB={on Shelf 4},
}
@book{goossens1994latex,
  title={The LaTeX Companion},
  author={Goossens, M. and Mittelbach, F. and Samarin, A.},
  isbn={9780201541991},
  lccn={lc93023150},
  series={Addison-Wesley series on tools and techniques for computer typesetting},
  url={https://books.google.com/books?id=54A3MuBzIrEC},
  year={1994},
  publisher={Addison-Wesley},
  myFieldA={Also Useful Book},
  myFieldB={on Shelf 5},
}
\end{filecontents}

%% -----------------

\documentclass{article}
\usepackage{biblatex}
\addbibresource{mybib.bib}

\begin{document}
    This should print ``Also Useful Book'':
    \citefield{goossens1994latex}{myFieldA}
\end{document}

Best Answer

Provided you only need a few fields, and are willing to sacrifice the markup semantics just a little bit (for the citations), you can get away with using the "custom fields" biblatex provides (the standard styles don't use them, but if you are using a non-standard one, you might have to check if it is really "vacant").

Given you mentioned in the comments that you'd like a custom name for your field, that can be achieved by using a SourceMap to copy the value from your custom field, to one of the available ones in biblatex's data model. This means you can have your custom name in your .bib file, but when actually making the citation you still have to use a field biblatex "knows".

This could go something like:

\begin{filecontents}[overwrite]{mybib.bib}
@book{knuth1984texbook,
  title={The texbook},
  author={Knuth, D.E. and Knuth, A.D. and Bibby, D. and American Mathematical Society and Addison-Wesley Publishing Company and Addison-Wesley},
  isbn={9780201134483},
  lccn={85030845},
  series={Computers \& typesetting},
  url={https://books.google.com/books?id=hEYuAQAAIAAJ},
  year={1984},
  publisher={Addison-Wesley},
  myFieldA={Useful Book},
  myFieldB={on Shelf 4},
}
@book{goossens1994latex,
  title={The LaTeX Companion},
  author={Goossens, M. and Mittelbach, F. and Samarin, A.},
  isbn={9780201541991},
  lccn={lc93023150},
  series={Addison-Wesley series on tools and techniques for computer typesetting},
  url={https://books.google.com/books?id=54A3MuBzIrEC},
  year={1994},
  publisher={Addison-Wesley},
  myFieldA={Also Useful Book},
  myFieldB={on Shelf 5},
}
\end{filecontents}

%% -----------------

\documentclass{article}
\usepackage{biblatex}
\addbibresource{mybib.bib}

\DeclareSourcemap{
  \maps[datatype=bibtex]{
    \map{
      \step[fieldsource=myFieldA]
      \step[fieldset=usera, origfieldval]
      \step[fieldsource=myFieldB]
      \step[fieldset=userb, origfieldval]
    }
  }
}

\begin{document}
This should print ``Also Useful Book'':
\citefield{goossens1994latex}{usera}

This should print ``on Shelf 5'':
\citefield{goossens1994latex}{userb}
\end{document}

The advantage of this approach is that you don't need to extend the data model, so it is simpler. But if you really need to use your custom field name on both sides then, as far as I can tell, the only way is to extend the data model to include your field. In which case, the canonical answer is the one by @moewe at: How can I create entirely new data types with BibLaTeX/Biber?.

Related Solutions

[Tex/LaTex] Related field in biblatex : page

Ok, I found a method, which I present it, in a simplified way (because it's a integreated in a more global project. For full details, see https://github.com/maieul/biblatex-manuscripts-philology/commit/cc76e0cd0a7d6952d407fa83229e1baeac89a27d.)

First, in the .bib file, create field "catalog", which will contain text formated as if it was arguments for cites commands:

@type{key,
  catalog={[xx]{key1}[yy]{key2}}
  }

In your .dbx file (see the handbook), say you want to have new field catalog:

\DeclareDatamodelFields[type=field,datatype=literal]{catalog}
\DeclareDatamodelEntryfields{catalog}

And in bbx file, say how you want to construct the final field

\DeclareStyleSourcemap{
    \maps[datatype=bibtex]{
        \map[overwrite]{
        \step[fieldsource=catalog,final]
        \step[fieldset=catalog,fieldvalue={\cites}]
        \step[origfieldval,fieldset=catalog,append]
        }
  }
}

So the field will be automatically transformed to

\cites[xx]{key1}[yy]{key2}

So, finally, call the field in finentry macro:

\renewbibmacro{\usebibmacro{catalog}\finentry} % new finentry macro
\newbibmacro{catalog}{%
\ifbibliography{}% print the catalogs only in final bibliography
    {\finentrypunct\setunit{}\par\unspace\printfield{catalog}}}%Check the punct, add a par break
    {}%
}
\DeclareFieldFormat{catalog}{% Format of the field
  \textbf{Cat.} % Should be more clean : with language string. See my full code
  #1%
}

[Tex/LaTex] Citing (author, journalabbr., year) needed

First thing to do is to add a field for the journal abbreviation to the article entrytype, journalabbr in the MWE. Therefore you need to declare a datamodel (an extra file; in the MWE I've used filecontents to simulate that) and you have to tell biblatex/biber to use it in the package options.

Then you have to modify the cite command, so it fits your needs. \citep from the authoryear-style (your citestyle) uses the \cite command. There you just have to add a switch, which checks if the field journalabbr is empty or not, and prints it out or not.

Last but not least you have to add the abbreviation fields to the entries.

MWE:

\begin{filecontents}{min.bib}
@article{boisson2003unexpected,
  title={Unexpected protein families including cell defense components feature in the N-myristoylome of a higher eukaryote},
  author={Boisson, B. and Giglione, Carmela and Meinnel, Thierry},
  journal={Journal of Biological Chemistry},
  journalabbr={JBC},
  year={2003},
  publisher={ASBMB}
}
\end{filecontents}

\begin{filecontents}{authorjabbryear.dbx}
\ProvidesFile{authorjabbryear.dbx}
\DeclareDatamodelFields[type=field,datatype=literal]{journalabbr}
\DeclareDatamodelEntryfields[article]{journalabbr}
\end{filecontents}

\documentclass[fontsize=11pt, paper=a4, ngerman, DIV=calc]{scrartcl}
\usepackage[scaled]{helvet}
\renewcommand*\familydefault{\sfdefault}
\usepackage{fixltx2e}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage{babel}
\usepackage[german=quotes]{csquotes}
\usepackage[style=authoryear-comp,sortcites=true,sorting=nyt,isbn=false,natbib=true, citestyle=authoryear,bibstyle=authoryear,backend=biber,maxnames=1,maxcitenames=1,
,datamodel=authorjabbryear%added!
] {biblatex}

\DefineBibliographyStrings{ngerman}{ andothers = {{et\,al\adddot}} }

\renewbibmacro*{cite}{%from authoryear.cbx
  \iffieldundef{shorthand}
    {\ifthenelse{\ifnameundef{labelname}\OR\iffieldundef{labelyear}}
       {\usebibmacro{cite:label}%
        \setunit{\addspace}}
       {\printnames{labelname}%
        \setunit{\nameyeardelim}}%
     \iffieldundef{journalabbr}{}{%
        \printfield{journalabbr}%
        \setunit{\nameyeardelim}%
        }%
     \usebibmacro{cite:labelyear+extrayear}}
    {\usebibmacro{cite:shorthand}}}

\addbibresource{min.bib}

\begin{document}

\citep{boisson2003unexpected} 

How it should look like: 

(Boisson et al., JBC, 2003)

\printbibliography

\end{document}