When is a foreign key check performed on an input/output field?

A foreign key check is performed on an input/output field when that field references a dictionary field that has a defined check table. This means that when the data entered in that field is saved or processed, the system verifies that the value provided corresponds to a valid entry in the associated check table.

Check tables are essential in ensuring data integrity within the database. They act as a reference, allowing the system to confirm that any value entered into the field adheres to the constraints set by the related table, which ensures that the relationships between different pieces of data remain consistent and valid. This mechanism is critical in avoiding orphaned records and maintaining relational database integrity.

The other options, while they mention aspects of data entry and validation, do not specifically relate to the concept of foreign key checks. Search definitions and value help may assist users in finding valid entries, but they do not enforce the referential constraints set by foreign keys as a check table does. Similarly, append search refers to a different mechanism that allows for entries to be suggested based on previous inputs but does not guarantee that the input adheres to the structure required by foreign keys.