\item{x}{A single-row data frame, or a string containing the variables and/or values that should be updated (a data frame is converted to a JSON object, strings are stored as-is)}
\item{index}{The name of the Elasticsearch index to update}
\item{varname}{String indicating the parent variable that should be updated (when it does not exist, it will be created, all varnames are prefixed by computerCodes)}