Perl in a Nutshell, 2nd Edition

Placeholders and Statement Handles

Many database drivers allow you to use question marks as placeholders in SQL statements and then bind values to the placeholders before executing them. This enables you to prepare a single statement with placeholders and reuse it for each row of the database. For example, the prepare statement might read:

$st_handle = $db_handle->prepare(q{
        insert into books (isbn, title) values (?, ?)
})  || die db_handle->errstr;

And a subsequent execute statement might read:

$st_handle->execute("1-56592-286-7", "Perl in a Nutshell") 
        || die $db_handle->errstr;