Is there a feature to restore a deleted entity, restoring it from the last record of the history?

[gridanjbf]

Suggestion

def rollback_deletion( id)
 h = Entity::History.where(id: id).last
 Entity.create(h.attributes.except("hid", "recorded_at", "validity"))

end

[tagliala]

Copilot generated answer

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If you want to restore a deleted entity from its history in ChronoModel, and re-create it with the original id, you can use:

Model.create!(Model::History.find(hid).attributes.slice(*Model.attribute_names))

Explanation:

• This line fetches the history entry, extracts its attributes, slices them to only those required by the current model (including id), and creates a new record.
• It assumes that the model's attributes have not changed incompatibly since the history was recorded.

Caveats:

• Associations: This only restores the main record. If your model has has_many or other associations with dependent: :destroy, those associated records will not be automatically restored. You would need to implement custom logic to walk through history records of those associations and restore them as well.
• Validations & Callbacks: If your model has validations or callbacks, create! may fail if the attributes from history don’t pass current requirements.
• Id collisions: If another record with the same id already exists, this will raise an error.

For associations:
To restore associated records, you’d need to:

1. Identify all associations with dependent: :destroy (or other destructive options).
2. Find and restore their history records, possibly recursively.

Example (pseudo-code):

model = Model.create!(Model::History.find(hid).attributes.slice(*Model.attribute_names))
Model.reflect_on_all_associations(:has_many).each do |assoc|
  next unless assoc.options[:dependent] == :destroy
  history_class = assoc.klass.const_get(:History)
  history_records = history_class.where("#{assoc.foreign_key}": model.id)
  history_records.each do |hr|
    assoc.klass.create!(hr.attributes.slice(*assoc.klass.attribute_names))
  end
end

Summary:
Restoring associations is non-trivial and must account for the specifics of your model and database constraints. For simple entities, the one-liner above will suffice; for more complex models, consider writing a service object or script tailored to your schema.

Let me know if you want help writing a generalized restoration script!