PL/SQL結(jié)構(gòu)

無(wú)名塊：未命名的程序塊

命名塊：指過(guò)程，函數(shù)，包和觸發(fā)器

定義部分：用于定義變量，常量，游標(biāo)，觸發(fā)器，復(fù)合數(shù)據(jù)類型

執(zhí)行部分：用于實(shí)現(xiàn)應(yīng)用模塊功能，包含了要執(zhí)行的PL/SQL語(yǔ)句和SQL語(yǔ)句

異常處理部分：用于處理執(zhí)行部分可能出現(xiàn)的運(yùn)行錯(cuò)誤

[DECLARE

...  --定義部分]

BEGIN

...  --執(zhí)行部分

[EXCEPTION

...  --異常處理部分]

END;

-------------------------------------

DECLARE

    a NUMBER;

BEGIN

    a:=1+2;

    DBMS_OUTPUT.PUT_LINE('1+2='||a);

EXCEPTION

    WHEN OTHERS THEN

        DBMS_OUTPUT.PUT_LINE('出現(xiàn)異常')

END;

/

條件分支語(yǔ)句：

DECLARE

    a1 number := 100;

    a2 number := 200;

BEGIN

    IF a1>a2 THEN

        DBMS_OUTPUT.PUT_LINE('a1 is larger than a2');

    ELSIF a1=a2 THEN

        DBMS_OUTPUT.PUT_LINE('a1 is equal to a2')

    ELSE

        DBMS_OUTPUT.PUT_LINE('a1 is smaller than a2');

    ENDIF;

END;

/

------------------------------------------------------------------------------------

DECLARE

    grade CHAR(1) := 'B';

    appraisal VARCHAR2(20);

BEGIN

    appraisal :=

    CASE grade

        WHEN 'A' THEN '優(yōu)'

        WHEN 'B' THEN '良'

        WHEN 'C' THEN '中'

        WHEN 'D' THEN '及格'

        WHEN 'F' THEN '不及格'

    ELSE '沒(méi)有這樣的等級(jí)'

    DBMS_OUTPUT.PUT_LINE('Grade'||grade||'is'||appraisal);

END;

/

循環(huán)語(yǔ)句：

DECLARE

    total number := 0;

    salary number := 1800;

BEGIN

    LOOP

        total := total + salary;

        EXIT WHEN total > 2500

    END LOOP;

    DBMS_OUTPUT.PUT_LINE('total salary is'||total);

END;

/

----------------------------------------------------------------------------

DECLARE

    total number := 0;

    salary number := 1800;

BEGIN

    WHILE total<2500 LOOP

        total := total + salary;

    END LOOP;

    DBMS_OUTPUT.PUT_LINE('total salary is'||total);

END;

/

---------------------------------------------------------------------------

DELARE

    I INTEGER;

BEGIN

    FOR I IN REVERSE 1..3 LOOP

        DBMS_OUTPUT.PUT_LINE(I);

    END LOOP;

END;

/