Another option is to use the PCRE (Perl Compatable Regular Expressions) loadable module for SQLite for familar pattern matching via the REGEXP function.

#!/usr/bin/perl
use warnings; use strict;
use  5.10.1;
use DBI;

my $dbh = DBI->connect("dbi:SQLite:dbname=/tmp/text.db", "", "", {Rais
+eError => 1});
# so we can use SQLite REGEXP operator
$dbh->sqlite_enable_load_extension(my $_enabled = 1);
$dbh->prepare("SELECT load_extension('/usr/lib/sqlite3/pcre.so')");

my $word = 'tag';
my $word_re = '\b'.quotemeta($word).'\b';

my $results  = $dbh->selectall_arrayref("SELECT ID, sentence  FROM tex
+ts WHERE sentence REGEXP ?", {}, $word_re);

foreach my $result (@$results) {
    my ($id, $sentence) = @$result;
    say "matched $id: $sentence";
}
[download]

Depending on your system it may be available as a package (Ubuntu has sqlite3-pcre).

It's also available from github https://github.com/oojah/sqlite3-pcre where you can build and install it yourself.