Collection Exceptions

The following table provides the collection exceptions(or we can say predefined exceptions) and when they are raised:

Exception	Raised when	Oracle Error
COLLECTION_IS_NULL	You try to operate on an atomically null collection.	ORA-06531
NO_DATA_FOUND	A subscript designates an element that was deleted	ORA-01403
SUBSCRIPT_BEYOND_COUNT	A subscript exceeds the number of elements in a collection	ORA-06533
SUBSCRIPT_OUTSIDE_LIMIT	A subscript is outside the legal range	ORA-06532
VALUE_ERROR	A subscript is null or not convertible to an integer	ORA-06502

 Raised in program:

DECLARE
TYPE NumList IS TABLE OF NUMBER;
nums NumList;  -- atomically null
BEGIN
/* Assume execution continues despite the raised exceptions. */
   nums(1) := 1;            -- raises COLLECTION_IS_NULL       (1)
   nums := NumList(1,2);  -- initialize table
   nums(NULL) := 3          -- raises VALUE_ERROR              (2)
   nums(0) := 3;            -- raises SUBSCRIPT_OUTSIDE_LIMIT  (3)
   nums(3) := 3;            -- raises SUBSCRIPT_BEYOND_COUNT   (4)
   nums.DELETE(1);  -- delete element 1

   IF nums(1) = 1 THEN ...  -- raises NO_DATA_FOUND            (5)

Example:

declare
  TYPE TYPE_NAME_NUM IS TABLE OF INTEGER;
  nums TYPE_NAME_NUM; /*:=TYPE_NAME_NUM(100,200,300,400)*/;
begin
  null;
  nums(1) := 1;
exception
  when COLLECTION_IS_NULL then
    dbms_output.put_line(sqlerrm);
/*ORA-06531: Reference to uninitialized collection*/
  
end;