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The Online Catalog (OPA) Data Model


What is the OPA Model?

The OPA model shows you the hierarchy or relationships between OPA descriptions and their creators.  The hierarchy involves a 'parent/child' relationship between records. For example, a series can be the parent of several items and a series can also be the child of a specific collection or record group.

The relationships between archival descriptions in OPA are as follows:

  • A series belongs to a record group or a collection.
  • A file unit belongs to a series.
  • An item can belong to a file unit or belong directly to a series.
  • Series, file units, and items only have one parent record.
  • Collections, record groups, series, and file units can have multiple child records.

Use your mouse cursor to click and learn more about each part of the OPA model.

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