An example of a pre-digital database is:

A library's card catalog is an example of a pre-digital database because it organizes information in a physical format, utilizing index cards to store bibliographic details about books and other resources. Each card represents a discrete piece of information about a particular title, author, or subject, and this system allows users to locate and access materials within the library.

In contrast, a cash register receipt, a doctor's office invoice, and a list of sales totals on a spreadsheet all fall into digital or semi-digital categories. Receipts and invoices may have transitioned to digital formats in many businesses, while spreadsheets are inherently digital tools used for data organization and analysis. Therefore, the card catalog distinctly represents an earlier, non-digital method of data management that predates the widespread use of computers and digital databases.