Final answer:
The triggers used for accessing system-set field values and to affect changes in other records are After Triggers. Before Triggers are for validating or modifying values before saving, while After Triggers are for working with system-assigned fields and related records post-saving.
Step-by-step explanation:
The triggers which are used to access field values that are system-set and to make changes in other records are After Triggers. Before Triggers are used to validate or change field values before they are saved to the database. However, After Triggers are used when you want to access field values that are set by the system, such as a record's ID or last modified date, which are only available after the record has been saved. They are also used when you want to affect changes to related records because related records are not locked during the before phase, and trying to modify them can lead to record-locking conflicts.
Both Before and After Triggers have their specific use cases and knowing when to use each is crucial for a correct system design. It's important to select the right one based on when you need to access the data and what actions you need to perform.