Which API call is necessary to add or update several records in a Quick Base app?

The correct choice for adding or updating several records in a Quick Base app is the API_ImportFromCSV call. This function is specifically designed to process multiple records at once by importing data from a CSV file. It allows for batch operations, making it efficient for scenarios where you need to add or modify multiple entries in a single action, rather than handling each record individually.

When you use API_ImportFromCSV, Quick Base reads the provided CSV data and can update existing records based on specified keys or create new records if those keys do not match any current entries. This capability is essential for data migration tasks or bulk updates where handling each record separately would be cumbersome and time-consuming.

The other choices do not fit this requirement as effectively. For example, API_SetKeyField is used to designate which field acts as the key for identifying records, and it does not deal directly with adding or updating multiple records. API_AddRecord is focused on adding a single record to the app and cannot process multiple entries in one call. API_PurgeRecords is intended for deleting records rather than adding or updating, which also makes it irrelevant for this task.