In the subroutines should I connect and disconnect the database every time

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can connection gone ?

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#!/usr/bin/perl
use DBI;
my $dbh = DBI->connect("dbi:SQLite:dbname=dbfile","","");

sub foo {
   my $sth = $dbh->prepare( $some_query );
   $sth->execute;
}

sub bar {
    my $result = $dbh->do( $other_query );
}