problem with bound columns and fetchall_arrayref with a slice

[Martin J. Evans]

Hi,

I've just hit a problem with bind_col and fetchall_arrayref when a slice is 
used and I'm wondering how I might fix it. I'm using DBD::Oracle and setting a 
bind type and some attributes but as soon as a slice is used in 
fetchall_arrayref, DBI rebinds the columns and I lose the column type and 
attribute. Here is an example:

# $sth is just a select with 4 column
# the first column is an integer and we want to keep it that way
# as the result will be JSONified and we don't want JSON to think it
# is a string and put quotes around it
$sth->bind_col (1, undef, {TYPE => SQL_INTEGER, DiscardString => 1});

my $list = $sth->fetchall_arrayref({});
print Dumper ($list);

Without the slice it produces:

$VAR1 = [
          [
            11,
            'Abandoned',
            '1358247475.860400',
            '1358247475.860400'
          ],

and with the slice it produces:

$VAR1 = [
          {
            'modified_date_time' => '1358247475.860400',
            'market_status_id' => '11',
            'name' => 'Abandoned',
            'created_date_time' => '1358247475.860400'
          },

Notice the slice caused the market_status_id to look like a string. This 
happens because DBI binds the columns when you use a slice and it is overriding 
what was set for column 1 in the bind this code does.

So this is how bind_col ends up being called:

BIND COL 1 (TYPE => SQL_INTEGER, DiscardString => 1)
BIND COL 1 (no type (i.e. type = 0) and no attrs)
BIND COL 2 (no type and no attrs)
BIND COL 3 (no type and no attrs)
BIND COL 4 (no type and no attrs)

The code in DBD::Oracle is possibly flawed in that every time bind_col is 
called it does:

        imp_sth->fbh[field-1].req_type = type;
        imp_sth->fbh[field-1].bind_flags = 0; /* default to none */

regardless of whether bind_col has been called before and set a type or 
attributes. As type is a parameter to dbd_st_bind_col anyone not wishing to set 
a type has to say 0.

I could fix my usage case by simply saying if bind_col has been called for a 
column which already has a type set and the incoming type is 0 don't touch it 
and if no attributes are passed don't clear any existing ones. It would work 
for me but I'd like to hear any comments.

Martin