The concept of Dangling References in Oracle PL/SQL
In Oracle PL/SQL, a dangling reference occurs when a program attempts to access or manipulate an object that no longer exists or has been removed.
This can happen in several ways, such as when a program tries to access a variable that has already been deallocated, or when a program tries to use a cursor that has been closed or invalidated.
Dangling references can lead to unpredictable behavior and errors in PL/SQL programs. To avoid dangling references, it's important to properly manage the lifetime of objects and to ensure that all references to objects are properly cleaned up when they are no longer needed.
One common technique for avoiding dangling references is to use exception handling to catch errors and ensure that objects are properly cleaned up before the program terminates. Another technique is to use RAISE_APPLICATION_ERROR to explicitly raise an error when a dangling reference is detected, allowing the program to gracefully handle the error and avoid any unexpected behavior.
Dangling reference example
SELECT product_id, log_datetime,
FROM pet_care_log_obj_table
WHERE product_id IS DANGLING