+use strict;
+use warnings;
+
package DBIx::Class::ResultSet::RecursiveUpdate;
-use version; $VERSION = qv('0.0.1');
+our $VERSION = '0.013';
-use warnings;
-use strict;
+use base qw(DBIx::Class::ResultSet);
+
+sub recursive_update {
+ my ( $self, $updates, $fixed_fields ) = @_;
+ return
+ DBIx::Class::ResultSet::RecursiveUpdate::Functions::recursive_update(
+ resultset => $self,
+ updates => $updates,
+ fixed_fields => $fixed_fields
+ );
+}
+
+package DBIx::Class::ResultSet::RecursiveUpdate::Functions;
use Carp;
+use Scalar::Util qw( blessed );
+use List::MoreUtils qw/ any /;
+
+sub recursive_update {
+ my %params = @_;
+ my ( $self, $updates, $fixed_fields, $object, $resolved,
+ $if_not_submitted )
+ = @params{
+ qw/resultset updates fixed_fields object resolved if_not_submitted/};
+ $resolved ||= {};
+
+ # warn 'entering: ' . $self->result_source->from();
+ carp 'fixed fields needs to be an array ref'
+ if $fixed_fields && ref($fixed_fields) ne 'ARRAY';
+ my %fixed_fields;
+ %fixed_fields = map { $_ => 1 } @$fixed_fields if $fixed_fields;
+ if ( blessed($updates) && $updates->isa('DBIx::Class::Row') ) {
+ return $updates;
+ }
+ if ( $updates->{id} ) {
+ $object = $self->find( $updates->{id}, { key => 'primary' } );
+ }
+ my @missing =
+ grep { !exists $updates->{$_} && !exists $fixed_fields{$_} }
+ $self->result_source->primary_columns;
+ if ( !$object && !scalar @missing ) {
-use base qw(DBIx::Class::ResultSet);
+ # warn 'finding by: ' . Dumper( $updates ); use Data::Dumper;
+ $object = $self->find( $updates, { key => 'primary' } );
+ }
+ $updates = { %$updates, %$resolved };
+ @missing =
+ grep { !exists $resolved->{$_} } @missing;
+ if ( !$object && !scalar @missing ) {
-sub recursive_update {
- my( $self, $updates ) = @_;
- my $object;
- $object = $self->find( $updates, { key => 'primary' } ) || $self->new( {} );
-
- for my $name ( keys %$updates ){
- if($object->can($name)){
- my $value = $updates->{$name};
-
- # updating relations that that should be done before the row is inserted into the database
- # like belongs_to
- if( $object->result_source->has_relationship($name)
- and
- ref $value
- ){
- my $info = $object->result_source->relationship_info( $name );
- if( $info and not $info->{attrs}{accessor} eq 'multi'
- and
- _master_relation_cond( $object, $info->{cond}, _get_pk_for_related( $object, $name ) )
- ){
- my $related_result = $object->related_resultset( $name );
- my $sub_object = $related_result->recursive_update( $value );
- $object->set_from_related( $name, $sub_object );
- }
+ # warn 'finding by +resolved: ' . Dumper( $updates ); use Data::Dumper;
+ $object = $self->find( $updates, { key => 'primary' } );
+ }
+ $object ||= $self->new( {} );
+
+ # warn Dumper( $updates ); use Data::Dumper;
+ # direct column accessors
+ my %columns;
+
+ # relations that that should be done before the row is inserted into the
+ # database like belongs_to
+ my %pre_updates;
+
+ # relations that that should be done after the row is inserted into the
+ # database like has_many, might_have and has_one
+ my %post_updates;
+ my %other_methods;
+ my %columns_by_accessor = _get_columns_by_accessor($self);
+
+ # warn 'resolved: ' . Dumper( $resolved );
+ # warn 'updates: ' . Dumper( $updates ); use Data::Dumper;
+ # warn 'columns: ' . Dumper( \%columns_by_accessor );
+ for my $name ( keys %$updates ) {
+ my $source = $self->result_source;
+
+ # columns
+ if ( exists $columns_by_accessor{$name}
+ && !( $source->has_relationship($name)
+ && ref( $updates->{$name} ) ) )
+ {
+
+ #warn "$name is a column\n";
+ $columns{$name} = $updates->{$name};
+ next;
+ }
+
+ # relationships
+ if ( $source->has_relationship($name) ) {
+ if ( _master_relation_cond( $self, $name ) ) {
+
+ #warn "$name is a pre-update rel\n";
+ $pre_updates{$name} = $updates->{$name};
+ next;
}
- # columns and other accessors
- elsif( $object->result_source->has_column($name)
- or
- !$object->can( 'set_' . $name )
- ) {
- $object->$name($value);
+ else {
+
+ #warn "$name is a post-update rel\n";
+ $post_updates{$name} = $updates->{$name};
+ next;
}
}
- #warn Dumper($object->{_column_data}); use Data::Dumper;
+
+ # many-to-many helper accessors
+ if ( is_m2m( $self, $name ) ) {
+
+ #warn "$name is a many-to-many helper accessor\n";
+ $other_methods{$name} = $updates->{$name};
+ next;
+ }
+
+ # accessors
+ if ( $object->can($name) && not $source->has_relationship($name) ) {
+
+ #warn "$name is an accessor";
+ $other_methods{$name} = $updates->{$name};
+ next;
+ }
+
+ # unknown
+ # TODO: don't throw a warning instead of an exception to give users
+ # time to adapt to the new API
+ $self->throw_exception(
+ "No such column, relationship, many-to-many helper accessor or generic accessor '$name'"
+ );
+ }
+
+ # warn 'other: ' . Dumper( \%other_methods ); use Data::Dumper;
+
+ # first update columns and other accessors
+ # so that later related records can be found
+ for my $name ( keys %columns ) {
+
+ #warn "update col $name\n";
+ $object->$name( $columns{$name} );
}
- _delete_empty_auto_increment($object);
- $object->update_or_insert;
+ for my $name ( keys %other_methods ) {
- # updating relations that can be done only after the row is inserted into the database
- # like has_many and many_to_many
- for my $name ( keys %$updates ){
+ #warn "update other $name\n";
+ $object->$name( $updates->{$name} );
+ }
+ for my $name ( keys %pre_updates ) {
+
+ #warn "pre_update $name\n";
+ _update_relation( $self, $name, $pre_updates{$name}, $object,
+ $if_not_submitted );
+ }
+
+ # $self->_delete_empty_auto_increment($object);
+ # don't allow insert to recurse to related objects
+ # do the recursion ourselves
+ # $object->{_rel_in_storage} = 1;
+ #warn "CHANGED: " . $object->is_changed . "\n":
+ #warn "IN STOR: " . $object->in_storage . "\n";
+ $object->update_or_insert if $object->is_changed;
+ $object->discard_changes;
+
+ # updating many_to_many
+ for my $name ( keys %$updates ) {
+ next if exists $columns{$name};
my $value = $updates->{$name};
- # many to many case
- if($object->can($name) and
- !$object->result_source->has_relationship($name) and
- $object->can( 'set_' . $name )
- ) {
- my ( $pk ) = _get_pk_for_related( $object, $name );
- my @values = @{$updates->{$name}};
- my @rows;
- my $result_source = $object->$name->result_source;
- @rows = $result_source->resultset->search({ $pk => [ @values ] } ) if @values;
- my $set_meth = 'set_' . $name;
- $object->$set_meth( \@rows );
- }
- elsif( $object->result_source->has_relationship($name) ){
- my $info = $object->result_source->relationship_info( $name );
- # has many case
- if( ref $updates->{$name} eq 'ARRAY' ){
- for my $sub_updates ( @{$updates->{$name}} ) {
- my $sub_object = $object->search_related( $name )->recursive_update( $sub_updates );
- }
+
+ if ( is_m2m( $self, $name ) ) {
+
+ #warn "update m2m $name\n";
+ my ($pk) = _get_pk_for_related( $self, $name );
+ my @rows;
+ my $result_source = $object->$name->result_source;
+ my @updates;
+ if ( !defined $value ) {
+ next;
+ }
+ elsif ( ref $value ) {
+ @updates = @{$value};
}
- # might_have and has_one case
- elsif ( ! _master_relation_cond( $object, $info->{cond}, _get_pk_for_related( $object, $name ) ) ){
- my $sub_object = $object->search_related( $name )->recursive_update( $value );
- #$object->set_from_related( $name, $sub_object );
+ else {
+ @updates = ($value);
+ }
+ for my $elem (@updates) {
+ if ( ref $elem ) {
+ push @rows,
+ recursive_update(
+ resultset => $result_source->resultset,
+ updates => $elem
+ );
+ }
+ else {
+ push @rows,
+ $result_source->resultset->find( { $pk => $elem } );
+ }
}
+ my $set_meth = 'set_' . $name;
+ $object->$set_meth( \@rows );
}
}
+ for my $name ( keys %post_updates ) {
+
+ #warn "post_update $name\n";
+ _update_relation( $self, $name, $post_updates{$name}, $object,
+ $if_not_submitted );
+ }
return $object;
}
-sub _delete_empty_auto_increment {
- my ( $object ) = @_;
- for my $col ( keys %{$object->{_column_data}}){
- if( $object->result_source->column_info( $col )->{is_auto_increment}
- and
- ( ! defined $object->{_column_data}{$col} or $object->{_column_data}{$col} eq '' )
- ){
- delete $object->{_column_data}{$col}
+# returns DBIx::Class::ResultSource::column_info as a hash indexed by column accessor || name
+sub _get_columns_by_accessor {
+ my $self = shift;
+ my $source = $self->result_source;
+ my %columns;
+ for my $name ( $source->columns ) {
+ my $info = $source->column_info($name);
+ $info->{name} = $name;
+ $columns{ $info->{accessor} || $name } = $info;
+ }
+ return %columns;
+}
+
+# Arguments: $rs, $name, $updates, $row, $if_not_submitted
+sub _update_relation {
+ my ( $self, $name, $updates, $object, $if_not_submitted ) = @_;
+
+ # this should never happen because we're checking the paramters passed to
+ # recursive_update, but just to be sure...
+ $object->throw_exception("No such relationship '$name'")
+ unless $object->has_relationship($name);
+
+ #warn "_update_relation $name: OBJ: " . ref($object) . "\n";
+
+ my $info = $object->result_source->relationship_info($name);
+
+ # get a related resultset without a condition
+ my $related_resultset =
+ $self->related_resultset($name)->result_source->resultset;
+ my $resolved;
+ if ( $self->result_source->can('_resolve_condition') ) {
+ $resolved =
+ $self->result_source->_resolve_condition( $info->{cond}, $name,
+ $object );
+ }
+ else {
+ $self->throw_exception(
+ "result_source must support _resolve_condition");
+ }
+
+ # warn "$name resolved: " . Dumper( $resolved ); use Data::Dumper;
+ $resolved = {}
+ if defined $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
+ && $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
+ == $resolved;
+
+ my @rel_cols = keys %{ $info->{cond} };
+ map {s/^foreign\.//} @rel_cols;
+
+ #warn "REL_COLS: " . Dumper(@rel_cols); use Data::Dumper;
+ my $rel_col_cnt = scalar @rel_cols;
+
+ # find out if all related columns are nullable
+ my $all_fks_nullable = 1;
+ for my $rel_col (@rel_cols) {
+ $all_fks_nullable = 0
+ unless $related_resultset->result_source->column_info($rel_col)
+ ->{is_nullable};
+ }
+
+ #warn "\tNULLABLE: $all_fks_nullable\n";
+ $if_not_submitted = $all_fks_nullable ? 'nullify' : 'delete'
+ unless defined $if_not_submitted;
+
+ # handle undef
+ #if (not defined $updates && $if_not_submitted eq 'delete') {
+ # warn "$name " . ref $object;
+ # $object->related_resultset($name)->delete;
+ # return;
+ #}
+
+ #warn "RELINFO for $name: " . Dumper($info); use Data::Dumper;
+
+ # the only valid datatype for a has_many rels is an arrayref
+ if ( $info->{attrs}{accessor} eq 'multi' ) {
+ $self->throw_exception(
+ "data for has_many relationship '$name' must be an arrayref")
+ unless ref $updates eq 'ARRAY';
+
+ my @updated_objs;
+
+ #warn "\tupdating has_many rel '$name' ($rel_col_cnt columns cols)\n";
+ for my $sub_updates ( @{$updates} ) {
+ my $sub_object = recursive_update(
+ resultset => $related_resultset,
+ updates => $sub_updates,
+ resolved => $resolved
+ );
+
+ push @updated_objs, $sub_object;
}
+
+ #warn "\tcreated and updated related rows\n";
+
+ my @cond;
+ my @related_pks = $related_resultset->result_source->primary_columns;
+
+ my $rs_rel_delist = $object->$name;
+
+ # foreign table has a single pk column
+ if ( scalar @related_pks == 1 ) {
+ $rs_rel_delist = $rs_rel_delist->search_rs(
+ { $related_pks[0] =>
+ { -not_in => [ map ( $_->id, @updated_objs ) ] }
+ }
+ );
+ }
+ # foreign table has multiple pk columns
+ else {
+ for my $obj (@updated_objs) {
+ my %cond_for_obj;
+ for my $col (@related_pks) {
+ $cond_for_obj{$col} = $obj->get_column($col);
+ }
+ push @cond, \%cond_for_obj;
+ }
+ $rs_rel_delist = $rs_rel_delist->search_rs({ -not => [@cond] });
+ }
+
+ #warn "\tCOND: " . Dumper(\%cond);
+ #my $rel_delist_cnt = $rs_rel_delist->count;
+ if ( $if_not_submitted eq 'delete' ) {
+
+ #warn "\tdeleting related rows: $rel_delist_cnt\n";
+ $rs_rel_delist->delete;
+
+ # # only handles related result classes with single primary keys
+ # if ( 1 == $rel_col_cnt ) {
+ # $object->$name->search(
+ # { $rel_cols[0] =>
+ # { -not_in => [ map ( $_->id, @updated_objs ) ] }
+ # }
+ # )->delete;
+ # }
+ # else {
+ # warn "multi-column relationships aren't supported\n";
+ # }
+ }
+ elsif ( $if_not_submitted eq 'set_to_null' ) {
+
+ #warn "\tnullifying related rows: $rel_delist_cnt\n";
+ my %update = map { $_ => undef } @rel_cols;
+ $rs_rel_delist->update( \%update );
+
+ # # only handles related result classes with single primary keys
+ # if ( 1 == $rel_col_cnt ) {
+ # $object->$name->search(
+ # { $rel_cols[0] =>
+ # { -not_in => [ map ( $_->id, @updated_objs ) ] }
+ # }
+ # )->update( { $rel_cols[0] => undef } );
+ # }
+ # else {
+ # warn "multi-column relationships aren't supported\n";
+ # }
+ }
+ }
+ elsif ($info->{attrs}{accessor} eq 'single'
+ || $info->{attrs}{accessor} eq 'filter' )
+ {
+
+ #warn "\tupdating rel '$name': $if_not_submitted\n";
+ my $sub_object;
+ if ( ref $updates ) {
+
+ # for might_have relationship
+ if ( $info->{attrs}{accessor} eq 'single'
+ && defined $object->$name )
+ {
+ $sub_object = recursive_update(
+ resultset => $related_resultset,
+ updates => $updates,
+ object => $object->$name
+ );
+ }
+ else {
+ $sub_object = recursive_update(
+ resultset => $related_resultset,
+ updates => $updates,
+ resolved => $resolved
+ );
+ }
+ }
+ else {
+ $sub_object = $related_resultset->find($updates)
+ unless (
+ !$updates
+ && ( exists $info->{attrs}{join_type}
+ && $info->{attrs}{join_type} eq 'LEFT' )
+ );
+ }
+ $object->set_from_related( $name, $sub_object )
+ unless (
+ !$sub_object
+ && !$updates
+ && ( exists $info->{attrs}{join_type}
+ && $info->{attrs}{join_type} eq 'LEFT' )
+ );
+ }
+ else {
+ $self->throw_exception(
+ "recursive_update doesn't now how to handle relationship '$name' with accessor "
+ . $info->{attrs}{accessor} );
}
}
-sub _get_pk_for_related {
- my ( $object, $relation ) = @_;
+sub is_m2m {
+ my ( $self, $relation ) = @_;
+ my $rclass = $self->result_class;
- my $rs = $object->result_source->resultset;
- my $result_source = _get_related_source( $rs, $relation );
- return $result_source->primary_columns;
+ # DBIx::Class::IntrospectableM2M
+ if ( $rclass->can('_m2m_metadata') ) {
+ return $rclass->_m2m_metadata->{$relation};
+ }
+ my $object = $self->new( {} );
+ if ( $object->can($relation)
+ and !$self->result_source->has_relationship($relation)
+ and $object->can( 'set_' . $relation ) )
+ {
+ return 1;
+ }
+ return;
}
-sub _get_related_source {
- my ( $rs, $name ) = @_;
- if( $rs->result_source->has_relationship( $name ) ){
- return $rs->result_source->related_source( $name );
+sub get_m2m_source {
+ my ( $self, $relation ) = @_;
+ my $rclass = $self->result_class;
+
+ # DBIx::Class::IntrospectableM2M
+ if ( $rclass->can('_m2m_metadata') ) {
+ return $self->result_source->related_source(
+ $rclass->_m2m_metadata->{$relation}{relation} )
+ ->related_source(
+ $rclass->_m2m_metadata->{$relation}{foreign_relation} );
}
+ my $object = $self->new( {} );
+ my $r = $object->$relation;
+ return $r->result_source;
+}
+
+sub _delete_empty_auto_increment {
+ my ( $self, $object ) = @_;
+ for my $col ( keys %{ $object->{_column_data} } ) {
+ if ($object->result_source->column_info($col)->{is_auto_increment}
+ and ( !defined $object->{_column_data}{$col}
+ or $object->{_column_data}{$col} eq '' )
+ )
+ {
+ delete $object->{_column_data}{$col};
+ }
+ }
+}
+
+sub _get_pk_for_related {
+ my ( $self, $relation ) = @_;
+ my $result_source;
+ if ( $self->result_source->has_relationship($relation) ) {
+ $result_source = $self->result_source->related_source($relation);
+ }
+
# many to many case
- my $row = $rs->new({});
- if ( $row->can( $name ) and $row->can( 'add_to_' . $name ) and $row->can( 'set_' . $name ) ){
- my $r = $row->$name;
- return $r->result_source;
+ if ( is_m2m( $self, $relation ) ) {
+ $result_source = get_m2m_source( $self, $relation );
}
- return;
+ return $result_source->primary_columns;
}
+# This function determines wheter a relationship should be done before or
+# after the row is inserted into the database
+# relationships before: belongs_to
+# relationships after: has_many, might_have and has_one
+# true means before, false after
sub _master_relation_cond {
- my ( $object, $cond, @foreign_ids ) = @_;
- my $foreign_ids_re = join '|', @foreign_ids;
- if ( ref $cond eq 'HASH' ){
- for my $f_key ( keys %{$cond} ) {
+ my ( $self, $name ) = @_;
+
+ my $source = $self->result_source;
+ my $info = $source->relationship_info($name);
+
+ #warn "INFO: " . Dumper($info) . "\n";
+
+ # has_many rels are always after
+ return 0
+ if $info->{attrs}->{accessor} eq 'multi';
+
+ my @foreign_ids = _get_pk_for_related( $self, $name );
+
+ #warn "IDS: " . join(', ', @foreign_ids) . "\n";
+
+ my $cond = $info->{cond};
+
+ sub _inner {
+ my ( $source, $cond, @foreign_ids ) = @_;
+
+ while ( my ( $f_key, $col ) = each %{$cond} ) {
+
# might_have is not master
- my $col = $cond->{$f_key};
- $col =~ s/self\.//;
- if( $object->column_info( $col )->{is_auto_increment} ){
+ $col =~ s/^self\.//;
+ $f_key =~ s/^foreign\.//;
+ if ( $source->column_info($col)->{is_auto_increment} ) {
return 0;
}
- if( $f_key =~ /^foreign\.$foreign_ids_re/ ){
+ if ( any { $_ eq $f_key } @foreign_ids ) {
return 1;
}
}
- }elsif ( ref $cond eq 'ARRAY' ){
- for my $new_cond ( @$cond ) {
- return 1 if _master_relation_cond( $object, $new_cond, @foreign_ids );
+ return 0;
+ }
+
+ if ( ref $cond eq 'HASH' ) {
+ return _inner( $source, $cond, @foreign_ids );
+ }
+
+ # arrayref of hashrefs
+ elsif ( ref $cond eq 'ARRAY' ) {
+ for my $new_cond (@$cond) {
+ return _inner( $source, $new_cond, @foreign_ids );
}
}
+ else {
+ $source->throw_exception(
+ "unhandled relation condition " . ref($cond) );
+ }
return;
}
-# Module implementation here
-
-
-1; # Magic true value required at end of module
+1; # Magic true value required at end of module
__END__
=head1 NAME
-DBIx::Class::ResultSet::RecursiveUpdate - like update_or_create - but recursive
+DBIx::Class::ResultSet::RecursiveUpdate - like update_or_create - but recursive
+=head1 SYNOPSIS
-=head1 VERSION
-
-This document describes DBIx::Class::ResultSet::RecursiveUpdate version 0.0.1
+The functional interface:
+
+ my $new_item = DBIx::Class::ResultSet::RecursiveUpdate::Functions::recursive_update({
+ resultset => $schema->resultset( 'Dvd' ),
+ updates => {
+ id => 1,
+ owned_dvds => [
+ {
+ title => 'One Flew Over the Cuckoo's Nest'
+ }
+ ]
+ }
+ });
-=head1 SYNOPSIS
+As ResultSet subclass:
- __PACKAGE__->load_namespaces( default_resultset_class => '+DBIx::Class::ResultSet::RecursiveUpdate' );
+ __PACKAGE__->load_namespaces( default_resultset_class => '+DBIx::Class::ResultSet::RecursiveUpdate' );
in the Schema file (see t/lib/DBSchema.pm). Or appriopriate 'use base' in the ResultSet classes.
Then:
-=for author to fill in:
-
my $user = $user_rs->recursive_update( {
id => 1,
owned_dvds => [
{
- id => undef,
title => 'One Flew Over the Cuckoo's Nest'
}
]
=head1 DESCRIPTION
-=for author to fill in:
- You can feed the ->create method with a recursive datastructure and have the related records
- created. Unfortunately you cannot do a similar thing with update_or_create - this module
- tries to fill that void.
- It is a base class for ResultSets providing just one method: recursive_update
- which works just like update_or_create but can recursively update or create
- data objects composed of multiple rows. All rows need to be identified by primary keys
- - so you need to provide them in the update structure (unless they can be deduced from
- the parent row - for example when you have a belongs_to relationship).
- When creating new rows in a table with auto_increment primary keys you need to
- put 'undef' for the key value - this is then removed
- and a correct INSERT statement is generated.
+This is still experimental. I've added a functional interface so that it can be used
+in Form Processors and not require modification of the model.
- For a many_to_many (pseudo) relation you can supply a list of primary keys
- from the other table - and it will link the record at hand to those and
- only those records identified by them. This is convenient for handling web
- forms with check boxes (or a SELECT box with multiple choice) that let you
- update such (pseudo) relations.
+You can feed the ->create method with a recursive datastructure and have the related records
+created. Unfortunately you cannot do a similar thing with update_or_create - this module
+tries to fill that void.
- For a description how to set up base classes for ResultSets see load_namespaces
- in DBIx::Class::Schema.
+It is a base class for ResultSets providing just one method: recursive_update
+which works just like update_or_create but can recursively update or create
+data objects composed of multiple rows. All rows need to be identified by primary keys
+- so you need to provide them in the update structure (unless they can be deduced from
+the parent row - for example when you have a belongs_to relationship).
+If not all colums comprising the primary key are specified - then a new row will be created,
+with the expectation that the missing columns will be filled by it (as in the case of auto_increment
+primary keys).
- The support for many to many pseudo relationships should be treated as prototype -
- the DBIC author disagrees with the way I did it.
+If the resultset itself stores an assignement for the primary key,
+like in the case of:
+
+ my $restricted_rs = $user_rs->search( { id => 1 } );
-=head1 INTERFACE
+then you need to inform recursive_update about additional predicate with a second argument:
+
+ my $user = $restricted_rs->recursive_update( {
+ owned_dvds => [
+ {
+ title => 'One Flew Over the Cuckoo's Nest'
+ }
+ ]
+ },
+ [ 'id' ]
+ );
+
+This will work with a new DBIC release.
+
+For a many_to_many (pseudo) relation you can supply a list of primary keys
+from the other table - and it will link the record at hand to those and
+only those records identified by them. This is convenient for handling web
+forms with check boxes (or a SELECT box with multiple choice) that let you
+update such (pseudo) relations.
+
+For a description how to set up base classes for ResultSets see load_namespaces
+in DBIx::Class::Schema.
+
+=head1 DESIGN CHOICES
+
+Columns and relationships which are excluded from the updates hashref aren't
+touched at all.
+
+=head2 Treatment of belongs_to relations
+
+In case the relationship is included but undefined in the updates hashref,
+all columns forming the relationship will be set to null.
+If not all of them are nullable, DBIx::Class will throw an error.
+
+Updating the relationship:
+
+ my $dvd = $dvd_rs->recursive_update( {
+ id => 1,
+ owner => $user->id,
+ });
+
+Clearing the relationship (only works if cols are nullable!):
-=for uthor to fill in:
+ my $dvd = $dvd_rs->recursive_update( {
+ id => 1,
+ owner => undef,
+ });
+
+=head2 Treatment of might_have relationships
+
+In case the relationship is included but undefined in the updates hashref,
+all columns forming the relationship will be set to null.
+
+Updating the relationship:
+
+ my $user = $user_rs->recursive_update( {
+ id => 1,
+ address => {
+ street => "101 Main Street",
+ city => "Podunk",
+ state => "New York",
+ }
+ });
+
+Clearing the relationship:
+
+ my $user = $user_rs->recursive_update( {
+ id => 1,
+ address => undef,
+ });
+
+=head2 Treatment of has_many relations
+
+If a relationship key is included in the data structure with a value of undef
+or an empty array, all existing related rows will be deleted, or their foreign
+key columns will be set to null.
+
+The exact behaviour depends on the nullability of the foreign key columns and
+the value of the "if_not_submitted" parameter. The parameter defaults to
+undefined which neither nullifies nor deletes.
+
+When the array contains elements they are updated if they exist, created when
+not and deleted if not included.
+
+=head3 All foreign table columns are nullable
+
+In this case recursive_update defaults to nullifying the foreign columns.
+
+=head3 Not all foreign table columns are nullable
+
+In this case recursive_update deletes the foreign rows.
+
+Updating the relationship:
+
+ Passing ids:
+
+ my $dvd = $dvd_rs->recursive_update( {
+ id => 1,
+ tags => [1, 2],
+ });
+
+ Passing hashrefs:
+
+ my $dvd = $dvd_rs->recursive_update( {
+ id => 1,
+ tags => [
+ {
+ id => 1,
+ file => 'file0'
+ },
+ {
+ id => 2,
+ file => 'file1',
+ },
+ ],
+ });
+
+ Passing objects:
+
+ TODO
+
+ You can even mix them:
+
+ my $dvd = $dvd_rs->recursive_update( {
+ id => 1,
+ tags => [ '2', { id => '3' } ],
+ });
+
+Clearing the relationship:
+
+ my $dvd = $dvd_rs->recursive_update( {
+ id => 1,
+ tags => undef,
+ });
+
+ This is the same as passing an empty array:
+
+ my $dvd = $dvd_rs->recursive_update( {
+ id => 1,
+ tags => [],
+ });
+
+=head2 Treatment of many-to-many pseudo relations
+
+The function gets the information about m2m relations from DBIx::Class::IntrospectableM2M.
+If it isn't loaded in the ResultSource classes the code relies on the fact that:
+
+ if($object->can($name) and
+ !$object->result_source->has_relationship($name) and
+ $object->can( 'set_' . $name )
+ )
+
+Then $name must be a many to many pseudo relation.
+And that in a similarly ugly was I find out what is the ResultSource of
+objects from that many to many pseudo relation.
+
+
+=head1 INTERFACE
=head1 METHODS
=head2 recursive_update
-The only method here.
+The method that does the work here.
+
+=head2 is_m2m
+
+$self->is_m2m( 'name ' ) - answers the question if 'name' is a many to many
+(pseudo) relation on $self.
+
+=head2 get_m2m_source
+
+$self->get_m2m_source( 'name' ) - returns the ResultSource linked to by the many
+to many (pseudo) relation 'name' from $self.
+
=head1 DIAGNOSTICS
=head1 CONFIGURATION AND ENVIRONMENT
-=for author to fill in:
-
DBIx::Class::RecursiveUpdate requires no configuration files or environment variables.
-
=head1 DEPENDENCIES
-=for author to fill in:
-
DBIx::Class
-None.
-
-
=head1 INCOMPATIBILITIES
-=for author to fill in:
-
None reported.
=head1 BUGS AND LIMITATIONS
-=for author to fill in:
-
No bugs have been reported.
Please report any bugs or feature requests to