What is the usage of a look-up as a data source?

A look-up as a data source is specifically utilized to return a single, specific data object that has been defined within the application. This function is critical when the application needs to retrieve precise information about a particular record, such as details pertaining to a customer or an order.

Using a look-up enables the application to efficiently retrieve this targeted information without the unnecessary overhead of processing multiple data objects. This function is common when the data source is structured to support direct queries that yield singular results, such as looking up by a unique identifier or key.

While some of the other options refer to broader data handling scenarios, they do not accurately describe the primary purpose of a look-up. For example, merging data from different applications or returning multiple objects do not align with the fundamental functionality of a look-up, which concentrates on obtaining one specific record. Similarly, caching pertains to performance optimization rather than the direct purpose of a data source look-up.