open INPUT,"<","input.xml" or die $!;
open OUTPUT,">","output.xml.tmp" or die $!;
while (<INPUT>) {
  s/<\/markers>/$database_row<\/markers>/;  # insert $database row before marker, if found on this line
  print OUTPUT $_;  # print line to output file
}
close INPUT;
close OUTPUT or die $!;
rename "output.xml.tmp","input.xml";