You could use Tie::File, but it sounds from your description as if you really don't need to. If each line is independant of all others, then you can just loop through one at a time. Just make sure you don't store anything that will accumulate over time. Just use a simple

while (<>){
  my @fields = split /\t/;
  #insert them into the database
}
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If there's more going on, then you'll have to tell us what's complicating it so we can figure out what else to suggest.