The data schema workbook for the ZIP Code and Administrative Reference File is included in the product delivery file downloaded from PDX. The current data schema workbook and earlier versions can also be downloaded using the following links:
ZIP Code and Administrative Boundaries Reference File Data Schema 2024.09 - Latest
ZIP Code and Administrative Boundaries Reference File Data Schema 2023.09 - 2024.09
Note: To access earlier versions not listed here, follow this link and use the Version dropdown to select the appropriate release.