Re: TYPE attribute in DBD::File related DBD's

On 30/07/2013 10:53, H.Merijn Brand wrote:
> The TYPE attribute is defined to be NUMERIC. Several databases do not
> follow that definition, like SQLite and CSV
>
> Luckily,  we control both DBD::CSV and the underlying DBD::File, se I
> can "fix" that for at least DBD::CSV and probably all DBD's using the
> DBD::File layer. I propose this change:
>
> --8<---
> diff --git a/lib/DBD/File.pm b/lib/DBD/File.pm
> index 444c4d4..ffc5e84 100644
> --- a/lib/DBD/File.pm
> +++ b/lib/DBD/File.pm
> @@ -280,6 +280,7 @@ my %supported_attrs = (
>       PRECISION => 1,
>       NULLABLE  => 1,
>       );
> +my $type_map;
>
>   sub FETCH
>   {
> @@ -306,8 +307,23 @@ sub FETCH
>
>              my @colnames = $sth->sql_get_colnames ();
>
> +           unless ($type_map) {
> +               $type_map = {   # Minimal type set (like CSV)
> +                   BLOB    => -4,
> +                   TEXT    => -1,
> +                   CHAR    =>  1,
> +                   INTEGER =>  4,
> +                   REAL    =>  7,
> +                   VARCHAR => 12,
> +                   };
> +               my $tia = $sth->{Database}->type_info_all ();
> +               # TYPE_NAME => DATA_TYPE
> +               $type_map->{$_->[0]} = $_->[1] for grep { ref $_ eq "ARRAY" } @$tia;

I have not looked at this in context but it seems to me this code is 
assuming element 0 and element 1 are TYPE_NAME and DATA_TYPE whereas 
type_info_all starts with a map which describes the columns in the result.

> +               }
> +
>              $attr eq "TYPE"      and
> -               return [ map { $sth->{f_overall_defs}{$_}{data_type}   || "CHAR" }
> +               return [ map { $type_map->{$_} || $_ }
> +                        map { $sth->{f_overall_defs}{$_}{data_type}   || "VARCHAR" }
>                              @colnames ];
>
>              $attr eq "PRECISION" and
> -->8---
>
> All DBI tests still pass, and several TODO tests in DBD::CSV now pass
>
> If DBD::xxx provides GetInfo.pm and TypeInfo.pm, the conversions will
> automatically be updated (once).

It will work as it stands so long as type_info_all maps type_name and data_type as indexes 0 and 1. If that changes it looks like it will break.

However, I might have misread this as I did not follow the context.

Martin