Here's the table in question.

create table db_column
( tab_id                int             not null
, col_num               int             not null
, col_name              varchar(50)     not null
, col_data_type         int             not null
, col_data_type_name    varchar(50)     not null
, col_charlength        int
, col_precision         int
, col_scale             int
, col_nullity           char(1)         not null
, constraint db_column0 primary key
    ( tab_id
    , col_num
    )
)
[download]

And the statement I was using to insert data looked like this:

my $addcol = $dbh->prepare(
    "insert into db_column
    ( tab_id
    , col_num
    , col_name
    , col_data_type
    , col_data_type_name
    , col_charlength
    , col_precision
    , col_scale
    , col_nullity
    )
    values (?, ?, ?, ?, ?, ?, ?, ?, ?)");
# later....
    $addcol->execute(
        $tabid,
        $ck->{order},
        $colname,
        $ck->{type},
        $dbh->sql_typename($ck->{type}),
        $ck->{charlength},
        $ck->{precision},
        $ck->{scale},
        ($ck->{nullity}? 'Y' : 'N'))
                or warn "Couldn't insert into db_column: $DBI::errstr"
+;
[download]

The program inserts around 4000 rows into this table in a typical run. The col_name column consistently had no more than four characters, and col_data_type_name had no more than seven. Similar truncation was happening in other tables as well.

For debugging, I printed the values just before calling execute to insert them, so I know they were correct at the time of the call. I could also insert the strings using a interactive SQL tool, so I know the table itself wasn't a problem. I ran with DBI->trace(5) so I could see the intact strings being passed down, and that there were no error messages. I poked around the http://dbi.perl.org archives but didn't find anything that seemed related to this.