Live ORACLE

DECLARE

  TYPE dnames_tab IS TABLE OF VARCHAR2(30);

   -- This nested table has some values

   dept_names  DNAMES_TAB := Dnames_tab('Shipping','Sales','Finance','Payroll');

   -- This nested table is not initialized ("atomically null").

   empty_set  DNAMES_TAB;

BEGIN

  -- At first, the initialized variable is not null.

  IF dept_names IS NOT NULL THEN

    dbms_output.Put_line('OK, at first dept_names is not null.');

  END IF;

 

  -- Then we assign a null nested table to it.

  dept_names := empty_set;

 

  -- Now it is null.

  IF dept_names IS NULL THEN

    dbms_output.Put_line('OK, now dept_names has become null.');

  END IF;

 

  -- We must use another constructor to give it some values.

  dept_names := Dnames_tab('Shipping','Sales','Finance','Payroll');

END;

/

Assigning a Null Value to a Nested Table