[Dbix-class] as_query() and DBIx::Class::Cursor::Cached aren't friends

[Rob Kinyon]

If it passes all the tests, that's fine. But, the cursor knows more
than the resultset because the resultset isn't a query - it's a set of
potential conditions that could become an UPDATE, DELETE, or SELECT.

Rob

On Mon, Jun 8, 2009 at 05:39, Peter Rabbitson <rabbit+dbic at rabbit.us> wrote:
> Rob Kinyon wrote:
>> On Sun, Jun 7, 2009 at 20:36, Peter Rabbitson <rabbit+dbic at rabbit.us> wrote:
>>> The fix should be quite simple, i.e. move as_query out of the Cursor
>>> class. But first I'd like someone to comment on why it ended up there
>>> in the first place.
>>
>> The only thing that has a query is the cursor. Everything else has the
>> building blocks of a query, but hasn't been materialized as such. A
>> ResultSet (which is where I originally thought to put it) can
>> materialize as all sorts of queries, so it can't live there.
>>
>
> But this makes no sense whatsoever. A cursor is just a cursor, it knows
> nothing more than what the resultset object already does. Consider:
>
> === lib/DBIx/Class/ResultSet.pm
> ==================================================================
> --- lib/DBIx/Class/ResultSet.pm (revision 6543)
> +++ lib/DBIx/Class/ResultSet.pm (local)
> @@ -1925,7 +1925,10 @@
>
>  =cut
>
> -sub as_query { return shift->cursor->as_query(@_) }
> +sub as_query {
> +  my $self = shift;
> +  return $self->result_source->storage->as_query($self);
> +}
>
>  =head2 find_or_new
>
> === lib/DBIx/Class/Storage/DBI/Cursor.pm
> ==================================================================
> --- lib/DBIx/Class/Storage/DBI/Cursor.pm        (revision 6543)
> +++ lib/DBIx/Class/Storage/DBI/Cursor.pm        (local)
> @@ -49,32 +49,6 @@
>   return bless ($new, $class);
>  }
>
> -=head2 as_query
> -
> -=over 4
> -
> -=item Arguments: none
> -
> -=item Return Value: \[ $sql, @bind ]
> -
> -=back
> -
> -Returns the SQL statement and bind vars associated with the invocant.
> -
> -=cut
> -
> -sub as_query {
> -  my $self = shift;
> -
> -  my $storage = $self->{storage};
> -  my $sql_maker = $storage->sql_maker;
> -  local $sql_maker->{for};
> -
> -  my @args = $storage->_select_args(@{$self->{args}});
> -  my ($sql, $bind)  = $storage->_prep_for_execute(@args[0 .. 2], [@args[4 .. $#args]]);
> -  return \[ "($sql)", @{ $bind || [] }];
> -}
> -
>  =head2 next
>
>  =over 4
> === lib/DBIx/Class/Storage/DBI.pm
> ==================================================================
> --- lib/DBIx/Class/Storage/DBI.pm       (revision 6543)
> +++ lib/DBIx/Class/Storage/DBI.pm       (local)
> @@ -910,6 +910,40 @@
>   return ($sql, \@bind);
>  }
>
> +=head2 as_query
> +
> +=over 4
> +
> +=item Arguments: none
> +
> +=item Return Value: \[ $sql, @bind ]
> +
> +=back
> +
> +Returns the SQL statement and bind vars that would result from the given
> +ResultSet (does not actually run a query)
> +
> +=cut
> +
> +sub as_query {
> +  my ($self, $rs) = @_;
> +
> +  my $sql_maker = $self->sql_maker;
> +  local $sql_maker->{for};
> +
> +  my $attr = $rs->_resolved_attrs;
> +
> +  # my ($op, $bind, $ident, $bind_attrs, $select, $cond, $order, $rows, $offset) = $self->_select_args(...);
> +  my @args = $self->_select_args($attr->{from}, $attr->{select}, $attr->{where}, $attr);
> +
> +  # my ($sql, $bind) = $self->_prep_for_execute($op, $bind, $ident, [ $select, $cond, $order, $rows, $offset ]);
> +  my ($sql, $bind) = $self->_prep_for_execute(
> +    @args[0 .. 2],
> +    [ @args[4 .. $#args] ],
> +  );
> +  return \[ "($sql)", @{ $bind || [] }];
> +}
> +
>  sub _fix_bind_params {
>     my ($self, @bind) = @_;
>
>
> I am not committing this until I get more input, but it seems rather
> straightforward to me.
>
>
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>



-- 
Thanks,
Rob Kinyon