Contents

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# ActiveFedora::Aggregation

Aggregations for ActiveFedora: manage a group of related objects using predicates from the
[OAI-ORE data model](http://www.openarchives.org/ore/1.0/datamodel).  Provides the foundation
for flexible relationships, including items appearing multiple times in a group,
flexible/optional ordering, etc.

Used extensively by [Hydra::PCDM](https://github.com/projecthydra-labs/hydra-pcdm/).

### Example
```ruby
class GenericFile < ActiveFedora::Base
end

generic_file1 = GenericFile.create(id: 'file1')
generic_file2 = GenericFile.create(id: 'file2')
generic_file3 = GenericFile.create(id: 'file2')

class Image < ActiveFedora::Base
  ordered_aggregation :generic_files, through: :list_source
end

image = Image.create(id: 'my_image')
image.ordered_generic_file_proxies.append_target generic_file2
image.ordered_generic_file_proxies.append_target generic_file1
image.save
image.generic_files # => [generic_file2, generic_file]
image.ordered_generic_files # => [generic_file2, generic_file]

# Not all generic files must be ordered.
image.generic_files += [generic_file3]
image.generic_files # => [generic_file2, generic_file, generic_file3]
image.ordered_generic_files # => [generic_file2, generic_file]

# non-ordered accessor is not ordered.
image.ordered_generic_file_proxies.insert_at(0, generic_file3)
image.generic_files # => [generic_file2, generic_file, generic_file3]
image.ordered_generic_files # => [generic_file3, generic_file2, generic_file]

# Deletions
image.ordered_generic_file_proxies.delete_at(1)
image.ordered_generic_files # => [generic_file3, generic_file]
```

Version data entries

5 entries across 5 versions & 1 rubygems

Version	Path
activefedora-aggregation-0.8.1	README.md
activefedora-aggregation-0.8.0	README.md
activefedora-aggregation-0.7.0	README.md
activefedora-aggregation-0.6.0	README.md
activefedora-aggregation-0.5.0	README.md