When is the auxiliary data table (Side Table) usually no longer used in a database?

The Side Table in iOS is typically used to store properties or information that cannot be directly added to an object, such as an instance of an Objective-C class, when the original class cannot be modified.

The Side Table stops being used when:

• The object or class no longer exists (memory is released).
• Additional data is no longer needed and is removed.
• Properties have been moved into the class or structure itself, eliminating the need for a separate table.

For example, in Swift, if you add an extension with computed properties that do not require storage, a Side Table is not needed. But if you need to store state that cannot be directly added, the Side Table is used as long as the object exists.

Thus, the Side Table is a temporary mechanism for storing additional data, which ceases to be used when the object is released or during code refactoring that removes the need for it.