public SQLMergeClause addFlag(Position position, String flag) {
        metadata.addFlag(new QueryFlag(position, flag));
        return this;
    }
public SQLMergeClause addFlag ( Position position , String flag ) { metadata . addFlag ( new QueryFlag ( position , flag ) ) ; return this ; }
Add the given String literal at the given position as a query flag

@param position position
@param flag query flag
@return the current object