1 package DBIx::Class::InflateColumn;
6 use base 'DBIx::Class::Row';
7 use DBIx::Class::_Util 'is_literal_value';
12 DBIx::Class::InflateColumn - Automatically create references from column data
16 # In your table classes
17 __PACKAGE__->inflate_column('column_name', {
19 my ($raw_value_from_db, $result_object) = @_;
23 my ($inflated_value_from_user, $result_object) = @_;
30 This component translates column data into references, i.e. "inflating"
31 the column data. It also "deflates" references into an appropriate format
34 It can be used, for example, to automatically convert to and from
35 L<DateTime> objects for your date and time fields. There's a
36 convenience component to actually do that though, try
37 L<DBIx::Class::InflateColumn::DateTime>.
39 It will handle all types of references except scalar references. It
40 will not handle scalar values, these are ignored and thus passed
41 through to L<SQL::Abstract>. This is to allow setting raw values to
42 "just work". Scalar references are passed through to the database to
43 deal with, to allow such settings as C< \'year + 1'> and C< \'DEFAULT' >
46 If you want to filter plain scalar values and replace them with
47 something else, see L<DBIx::Class::FilterColumn>.
53 Instruct L<DBIx::Class> to inflate the given column.
55 In addition to the column name, you must provide C<inflate> and
56 C<deflate> methods. The C<inflate> method is called when you access
57 the field, while the C<deflate> method is called when the field needs
58 to used by the database.
60 For example, if you have a table C<events> with a timestamp field
61 named C<insert_time>, you could inflate the column in the
62 corresponding table class using something like:
64 __PACKAGE__->inflate_column('insert_time', {
66 my ($insert_time_raw_value, $event_result_object) = @_;
67 DateTime->from_epoch( epoch => $insert_time_raw_value );
70 my ($insert_time_dt_object, $event_result_object) = @_;
71 $insert_time_dt_object->epoch;
75 The coderefs you set for inflate and deflate are called with two parameters,
76 the first is the value of the column to be inflated/deflated, the second is
77 the result object itself.
79 In this example, calls to an event's C<insert_time> accessor return a
80 L<DateTime> object. This L<DateTime> object is later "deflated" back
81 to the integer epoch representation when used in the database layer.
82 For a much more thorough handling of the above example, please see
83 L<DBIx::Class::DateTime::Epoch>
88 my ($self, $col, $attrs) = @_;
90 my $colinfo = $self->column_info($col);
92 $self->throw_exception("InflateColumn can not be used on a column with a declared FilterColumn filter")
93 if defined $colinfo->{_filter_info} and $self->isa('DBIx::Class::FilterColumn');
95 $self->throw_exception("No such column $col to inflate")
96 unless $self->has_column($col);
97 $self->throw_exception("inflate_column needs attr hashref")
98 unless ref $attrs eq 'HASH';
99 $colinfo->{_inflate_info} = $attrs;
100 my $acc = $colinfo->{accessor};
101 $self->mk_group_accessors('inflated_column' => [ (defined $acc ? $acc : $col), $col]);
105 sub _inflated_column {
106 my ($self, $col, $value) = @_;
107 return $value unless defined $value; # NULL is NULL is NULL
109 my $info = $self->column_info($col)
110 or $self->throw_exception("No column info for $col");
112 return $value unless exists $info->{_inflate_info};
114 my $inflate = $info->{_inflate_info}{inflate};
115 $self->throw_exception("No inflator for $col") unless defined $inflate;
117 return $inflate->($value, $self);
120 sub _deflated_column {
121 my ($self, $col, $value) = @_;
123 ## Deflate any refs except for literals, pass through plain values
127 is_literal_value($value)
130 my $info = $self->column_info($col) or
131 $self->throw_exception("No column info for $col");
133 return $value unless exists $info->{_inflate_info};
135 my $deflate = $info->{_inflate_info}{deflate};
136 $self->throw_exception("No deflator for $col") unless defined $deflate;
138 return $deflate->($value, $self);
141 =head2 get_inflated_column
143 my $val = $obj->get_inflated_column($col);
145 Fetch a column value in its inflated state. This is directly
146 analogous to L<DBIx::Class::Row/get_column> in that it only fetches a
147 column already retrieved from the database, and then inflates it.
148 Throws an exception if the column requested is not an inflated column.
152 sub get_inflated_column {
153 my ($self, $col) = @_;
154 $self->throw_exception("$col is not an inflated column")
155 unless exists $self->column_info($col)->{_inflate_info};
156 return $self->{_inflated_column}{$col}
157 if exists $self->{_inflated_column}{$col};
159 my $val = $self->get_column($col);
161 return $val if is_literal_value($val); #that would be a not-yet-reloaded literal update
163 return $self->{_inflated_column}{$col} = $self->_inflated_column($col, $val);
166 =head2 set_inflated_column
168 my $copy = $obj->set_inflated_column($col => $val);
170 Sets a column value from an inflated value. This is directly
171 analogous to L<DBIx::Class::Row/set_column>.
175 sub set_inflated_column {
176 my ($self, $col, $inflated) = @_;
177 $self->set_column($col, $self->_deflated_column($col, $inflated));
179 if (length ref $inflated and ! is_literal_value($inflated) ) {
180 $self->{_inflated_column}{$col} = $inflated;
182 delete $self->{_inflated_column}{$col};
187 =head2 store_inflated_column
189 my $copy = $obj->store_inflated_column($col => $val);
191 Sets a column value from an inflated value without marking the column
192 as dirty. This is directly analogous to L<DBIx::Class::Row/store_column>.
196 sub store_inflated_column {
197 my ($self, $col, $inflated) = @_;
199 if (is_literal_value($inflated)) {
200 delete $self->{_inflated_column}{$col};
201 $self->store_column($col => $inflated);
204 delete $self->{_column_data}{$col};
205 $self->{_inflated_column}{$col} = $inflated;
215 =item L<DBIx::Class::Core> - This component is loaded as part of the
216 C<core> L<DBIx::Class> components; generally there is no need to
223 Matt S. Trout <mst@shadowcatsystems.co.uk>
227 Daniel Westermann-Clark <danieltwc@cpan.org> (documentation)
229 Jess Robinson <cpan@desert-island.demon.co.uk>
233 You may distribute this code under the same terms as Perl itself.