Which types of formula field should you use to create a key field?

Using a Formula-Text field to create a key field is appropriate because key fields in Quickbase uniquely identify each record within a table. A text field allows for a variety of formats, such as alphanumeric values, which can be easily generated and maintained to ensure each record has a distinct identifier.

When using a Formula-Text field, you can dynamically generate values based on other fields in the record or static values, helping maintain uniqueness. This flexibility is crucial for creating a key field that meets the specific requirements of your application.

Other types of formula fields, like Formula-User, Formula-Numeric, and Formula-URL, serve different purposes. Formula-User is designed to hold user information, while Formula-Numeric is best for mathematical calculations and storing numeric values. Formula-URL is utilized for generating hyperlinks, which does not serve the purpose of uniquely identifying records. Therefore, a Formula-Text field is the most suitable choice for creating a key field in Quickbase.