PLSQL Language Referenc-PL/SQL集合和記錄-集合比較-和NULL比較可變陣列和巢狀表變數

DECLARE 

    TYPE Foursome IS VARRAY(4) OF VARCHAR2(15);  -- 可變陣列

    team Foursome;                              

    TYPE Roster IS TABLE OF VARCHAR2(15);        -- 巢狀表

    names Roster := Roster('AAAA', 'BBBB');  

BEGIN

    IF team IS NULL THEN

        DBMS_OUTPUT.PUT_LINE('team IS NULL');

    ELSE

        DBMS_OUTPUT.PUT_LINE('team IS NOT NULL');

    END IF;

    IF names IS NOT NULL THEN

        DBMS_OUTPUT.PUT_LINE('names IS NOT NULL');

    ELSE

        DBMS_OUTPUT.PUT_LINE('names IS NULL');

    END IF;

END;