（Perl）使用SQL :: Abstract创建DBI查询

Question

I want to add new record to table1 on SQLite

use SQL::Abstract;
my %data = (
  id => \'max(id)', # it is doesn't work so which variant is right?
  record => 'Something'
);

my $sql = SQL::Abstract->new;

my ($stmt, @bind) = $sql->insert('table1', \%data);


...
my $sth = $dbh->prepare($stmt);

If I used DBIx::Class in Catalyst app I would written like so:

id => $c->model('Model')->get_column('id')->max()

and it will work fine. So how can I reach the same aim but using just SQL::Abstract which is used in DBIx::Class as well. Could someone fixed it? Thanks.

Answer 1

This is a piece of code. As you can see, first you need to get the max id+1 and then do the insert command. I have to notice you this is not safe, because in a multi-(user,process,thread) environment, a second process can execute the same code and get race conditions. But I assume you are just learning the SQL::Abstract api, and that problem doesn't matter

use DBI;
use SQL::Abstract;

#create table TEST(ID integer, NAME varchar);
my $dbh = DBI->connect('dbi:SQLite:dbname=test.db', '', '', {AutoCommit=>1});

my $sql = SQL::Abstract->new;

my($stmt, @bind) = $sql->select("TEST", [ 'max(ID)+1 as ID' ] );
my $sth = $dbh->prepare($stmt);
$sth->execute(@bind);

my ($id) = $sth->fetchrow_array // 1;

print "Select ID: $id", "\n";
$sth->finish;

($stmt, @bind) = $sql->insert("TEST", { ID=>$id, NAME=>"test-name"} );
$sth = $dbh->prepare($stmt);
$sth->execute(@bind);

$dbh->disconnect;