Provided by: libdbix-class-resultset-recursiveupdate-perl_0.34-2_all 
NAME
DBIx::Class::ResultSet::RecursiveUpdate - like update_or_create - but recursive
VERSION
version 0.34
SYNOPSIS
# The functional interface:
my $schema = MyDB::Schema->connect();
my $new_item = DBIx::Class::ResultSet::RecursiveUpdate::Functions::recursive_update(
resultset => $schema->resultset('User'),
updates => {
id => 1,
owned_dvds => [
{
title => "One Flew Over the Cuckoo's Nest"
}
]
},
unknown_params_ok => 1,
);
# As ResultSet subclass:
__PACKAGE__->load_namespaces( default_resultset_class => '+DBIx::Class::ResultSet::RecursiveUpdate' );
# in the Schema file (see t/lib/DBSchema.pm). Or appropriate 'use base' in the ResultSet classes.
my $user = $schema->resultset('User')->recursive_update({
id => 1,
owned_dvds => [
{
title => "One Flew Over the Cuckoo's Nest"
}
]
}, {
unknown_params_ok => 1,
});
# You'll get a warning if you pass non-result specific data to
# recursive_update. See L</"Additional data in the updates hashref">
# for more information how to prevent this.
DESCRIPTION
You can feed the ->create method of DBIx::Class 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 until DBIx::Class has an api itself.
The functional interface can be used without modifications of the model, for example by
form processors like HTML::FormHandler::Model::DBIC.
It is a base class for DBIx::Class::ResultSets providing the method recursive_update which
works just like update_or_create but can recursively update or create result 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 a related row of a belongs_to relationship). If any of the primary key columns are
missing, 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).
If the resultset itself stores an assignment for the primary key, like in the case of:
my $restricted_rs = $user_rs->search( { id => 1 } );
you need to inform recursive_update about the additional predicate with the fixed_fields
attribute:
my $user = $restricted_rs->recursive_update( {
owned_dvds => [
{
title => 'One Flew Over the Cuckoo's Nest'
}
]
},
{
fixed_fields => [ 'id' ],
}
);
For a many_to_many (pseudo) relation you can supply a list of primary keys from the other
table and it will link the record at hand to those and only those records identified by
them. This is convenient for handling web forms with check boxes (or a select field with
multiple choice) that lets you update such (pseudo) relations.
For a description how to set up base classes for ResultSets see "load_namespaces" in
DBIx::Class::Schema.
Additional data in the updates hashref
If you pass additional data to recursive_update which doesn't match a column name, column
accessor, relationship or many-to-many helper accessor, it will throw a warning by
default. To disable this behaviour you can set the unknown_params_ok attribute to a true
value.
The warning thrown is: "No such column, relationship, many-to-many helper accessor or
generic accessor '$key'"
When used by HTML::FormHandler::Model::DBIC this can happen if you have additional form
fields that aren't relevant to the database but don't have the noupdate attribute set to a
true value.
NOTE: in a future version this behaviour will change and throw an exception instead of a
warning!
DESIGN CHOICES
Columns and relationships which are excluded from the updates hashref aren't touched at
all.
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!):
my $dvd = $dvd_rs->recursive_update( {
id => 1,
owner => undef,
});
Updating a relationship including its (full) primary key:
my $dvd = $dvd_rs->recursive_update( {
id => 1,
owner => {
id => 2,
name => "George",
},
});
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,
});
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.
All foreign table columns are nullable
In this case recursive_update defaults to nullifying the foreign columns.
Not all foreign table columns are nullable
In this case recursive_update deletes the foreign rows.
Updating the relationship:
Passing ids:
my $user = $user_rs->recursive_update( {
id => 1,
owned_dvds => [1, 2],
});
Passing hashrefs:
my $user = $user_rs->recursive_update( {
id => 1,
owned_dvds => [
{
name => 'temp name 1',
},
{
name => 'temp name 2',
},
],
});
Passing objects:
my $user = $user_rs->recursive_update( {
id => 1,
owned_dvds => [ $dvd1, $dvd2 ],
});
You can even mix them:
my $user = $user_rs->recursive_update( {
id => 1,
owned_dvds => [ 1, { id => 2 } ],
});
Clearing the relationship:
my $user = $user_rs->recursive_update( {
id => 1,
owned_dvds => undef,
});
This is the same as passing an empty array:
my $user = $user_rs->recursive_update( {
id => 1,
owned_dvds => [],
});
Treatment of many-to-many pseudo relations
If a many-to-many accessor key is included in the data structure with a value of undef or
an empty array, all existing related rows are unlinked.
When the array contains elements they are updated if they exist, created when not and
deleted if not included.
RecursiveUpdate defaults to calling 'set_$rel' to update many-to-many relationships. See
"many_to_many" in DBIx::Class::Relationship for details. set_$rel effectively removes and
re-adds all relationship data, even if the set of related items did not change at all.
If DBIx::Class::IntrospectableM2M is in use, RecursiveUpdate will look up the
corresponding has_many relationship and use this to recursively update the many-to-many
relationship.
While both mechanisms have the same final result, deleting and re-adding all relationship
data can have unwanted consequences if triggers or method modifiers are defined or logging
modules like DBIx::Class::AuditLog are in use.
The traditional "set_$rel" behaviour can be forced by passing "m2m_force_set_rel => 1" to
recursive_update.
See "is_m2m" for many-to-many pseudo relationship detection.
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:
my $dvd = $dvd_rs->recursive_update( {
id => 1,
tags => [ $tag1, $tag2 ],
});
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 = $dvd_rs->recursive_update( {
id => 1,
tags => [],
});
Make sure that set_$rel used to update many-to-many relationships even if
IntrospectableM2M is loaded:
my $dvd = $dvd_rs->recursive_update( {
id => 1,
tags => [1, 2],
},
{ m2m_force_set_rel => 1 },
);
INTERFACE
METHODS
recursive_update
The method that does the work here.
is_m2m
Arguments: $name
Return Value: true, if $name is a many to many pseudo-relationship
The function gets the information about m2m relations from DBIx::Class::IntrospectableM2M.
If it isn't loaded in the ResultSource class, the code relies on the fact:
if($object->can($name) and
!$object->result_source->has_relationship($name) and
$object->can( 'set_' . $name )
)
to identify a many to many pseudo relationship. In a similar ugly way the ResultSource of
that many to many pseudo relationship is detected.
So if you need many to many pseudo relationship support, it's strongly recommended to load
DBIx::Class::IntrospectableM2M in your ResultSource class!
get_m2m_source
Arguments: $name
Return Value: $result_source
CONFIGURATION AND ENVIRONMENT
DBIx::Class::RecursiveUpdate requires no configuration files or environment variables.
DEPENDENCIES
DBIx::Class
optional but recommended:
DBIx::Class::IntrospectableM2M
INCOMPATIBILITIES
None reported.
BUGS AND LIMITATIONS
The list of reported bugs can be viewed at
<http://rt.cpan.org/Public/Dist/Display.html?Name=DBIx-Class-ResultSet-RecursiveUpdate>.
Please report any bugs or feature requests to
"bug-DBIx-Class-ResultSet-RecursiveUpdate@rt.cpan.org", or through the web interface at
<http://rt.cpan.org>.
AUTHORS
• Zbigniew Lukasiak <zby@cpan.org>
• John Napiorkowski <jjnapiork@cpan.org>
• Alexander Hartmaier <abraxxa@cpan.org>
• Gerda Shank <gshank@cpan.org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2013 by Zbigniew Lukasiak, John Napiorkowski, Alexander
Hartmaier.
This is free software; you can redistribute it and/or modify it under the same terms as
the Perl 5 programming language system itself.
perl v5.20.0 2014-02-0DBIx::Class::ResultSet::RecursiveUpdate(3pm)