RE: Normalization of values from the database

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From: Johan Lindstrom Sent: 21 July 2004 11:40
>
>When I insert and then select values from a column of type
"numeric(19,4)",=20
>I get back numers like 32.5000 instead of 32.5 . I'd like to=20
>normalize/massage those values before they get to my application.
>
>Class::DBI provides code for a "normalize" phase, but that only applies

>when setting values from code, not when obtaining values from the
database=20
>(or does it?). It would be handy to have something like that on the way
up=20
>as well, but in the mean time I added a "select" trigger for this
purpose.
>
> <ecode>
> sub numify { my $self =3D shift;
> 	my ($name) =3D @_;
>	defined($self->{$name}) and $self->{$name} +=3D 0;
> }
> __PACKAGE__->add_trigger(select  =3D> sub { my $self =3D shift;
> 	$self->numify("account_amount");
> });
> </ecode>
>
>Note the direct hash key access (bad). But if I used the getter for
$name,=20
>that column would be auto-fleshed out if the value isn't already
selected,=20
>correct?

If you want to access the data without triggering all the db stuff
there are a set of methods, see LOW-LEVEL DATA ACCESS in the docs.
e.g. for your code...

 <ecode>
 sub numify { my $self =3D shift;
 	my ($name) =3D @_;
=09
 	defined($self->_attrs($name))=20
	and $self->_attribute_set($self->_attrs($name)+0);
 }
 </ecode>

>Is there a better way of doing this?
>Is there a better way to figure out if the value is already loaded or
not?

 $self->_attribute_exists($name)

>Things I just thought about(tm):
>* Maybe I should use the setter to assign the value at least.
>* exists is probably better than defined, on account of NULL values.
>
>/J


mark
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