This functionality is also available pre-rolled in DBIx::SQLEngine:

my ($sql, @params) = DBIx::SQLEngine->sql_insert( 
                       table => 'users', values => \%user_rec );
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There's also a dbh wrapper method that allows you to prepare and execute the query in one go:

my $sqldbh = DBIx::SQLEngine->new( ... ); # same args as DBI->connect
...
$sqldbh->do_insert( table => 'users', values => \%user_rec );
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