Class: Pageflow::NestedRevisionComponentCopy

Inherits:
Object
  • Object
show all
Defined in:
app/models/pageflow/nested_revision_component_copy.rb

Overview

Service object for copying nested revision components between records using bulk INSERT … SELECT statements.

When ‘reset_perma_ids` is false we reuse the perma_id values from the source revision. Parents and their copies are joined via perma_id so that foreign keys of the newly inserted records point at the duplicated parents.

If ‘reset_perma_ids` is true we compute an offset for each association. The offset ensures that the minimum perma_id of the records being copied becomes `entry.perma_id_counter + 1`. This yields a range of new perma_ids above the current maximum perma_id of the entry while preserving the relative order of ids within the copied set.

Example for a simple one level association:

INSERT INTO test_nested_revision_components (parent_id, perma_id, text)
SELECT NEW_ROOT_ID, old_items.perma_id + OFFSET, old_items.text
FROM test_nested_revision_components AS old_items
WHERE old_items.parent_id = OLD_ROOT_ID;

Example for a deeply nested association where nested items have parents of the same type:

INSERT INTO test_deeply_nested_revision_components (parent_id, perma_id)
SELECT new_children.id,
       old_deep_items.perma_id + OFFSET,
       old_deep_items.text
FROM test_deeply_nested_revision_components AS old_deep_items
JOIN test_nested_revision_components AS old_children
  ON old_children.id = old_deep_items.parent_id
JOIN test_nested_revision_components AS new_children
  ON new_children.parent_id = NEW_ROOT_ID
 AND new_children.perma_id = old_children.perma_id + CHILD_OFFSET
WHERE old_children.parent_id = OLD_ROOT_ID;

Defined Under Namespace

Classes: Model

Instance Method Summary collapse

Constructor Details

#initialize(from:, to:, reset_perma_ids: false, connection: ActiveRecord::Base.connection) ⇒ NestedRevisionComponentCopy

Returns a new instance of NestedRevisionComponentCopy.



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# File 'app/models/pageflow/nested_revision_component_copy.rb', line 38

def initialize(from:, to:, reset_perma_ids: false, connection: ActiveRecord::Base.connection)
  @root_class = from.class
  @old_root_id = from.id
  @new_root_id = to.id

  @reset_perma_ids = reset_perma_ids
  @connection = connection

  @offsets = Hash.new(0)
  @entry = to.entry_for_auto_generated_perma_id
end

Instance Method Details

#perform_for(revision_components:) ⇒ Object 



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# File 'app/models/pageflow/nested_revision_component_copy.rb', line 50

def perform_for(revision_components:)
  perform(Model.for(revision_components:))
end

#perform_for_nested_revision_components ⇒ Object 



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# File 'app/models/pageflow/nested_revision_component_copy.rb', line 54

def perform_for_nested_revision_components
  perform(Model.for_nested_revision_components(@root_class))
end