Final answer:
A validation rule with the VLOOKUP function can be used to ensure the Product Name and Product Code entered are valid according to a custom object in Universal Containers' order management application.
Step-by-step explanation:
To ensure that the Product Name and Product Code entered in the order management application are consistent with the valid combinations set up in a custom object, a developer can use a validation rule with the VLOOKUP function. This function will check the entered Product Code against a table of valid Product Name and Product Code combinations. If there is no match found, the validation rule will return an error, preventing the record from being saved. A validation rule is a declarative way to enforce data integrity rules in Salesforce without writing any code.