使用oralce Cursor

王朝other·作者佚名  2006-01-09
窄屏简体版  字體: |||超大  

使用Cursor:

declare

RoomID Room.RoomID%Type;

RoomName Room.RoomName%Type;

cursor crRoom is

select RoomID,RoomName

from Room;

begin

open crRoom;

loop;

fetch crRoom into RoomID,RoomName;

exit when crRoom%notFound;

end loop;

close crRoom;

end;

3.1在游标使用入口参数

在SQL语句的Where 子句中恰当使用 相关语句简化逻辑,本来需要使用两个游标,把相关入口参数放入到SQL语句的Where 子句中,一个就搞定了:

cursor crRoom is

select

distinct 楼层,房屋用途

from TT_没有处理的房屋 t

where 数据级别>= 0

and 房屋处理类别= 3

and 产权编号=p_产权编号

and 拆迁房屋类别=p_拆迁房屋类别

and 面积>0

and (not p_房屋用途 is null

and 房屋用途=p_房屋用途

or p_房屋用途 is null);

另外一个例子:

CREATE OR REPLACE PROCEDURE PrintStudents(

p_Major IN students.major%TYPE) AS

CURSOR c_Students IS

SELECT first_name, last_name

FROM students

WHERE major = p_Major;

BEGIN

FOR v_StudentRec IN c_Students LOOP

DBMS_OUTPUT.PUT_LINE(v_StudentRec.first_name || ' ' ||

v_StudentRec.last_name);

END LOOP;

END;

Oracle带的例子examp6.sql

DECLARE

CURSOR bin_cur(part_number NUMBER) IS SELECT amt_in_bin

FROM bins

WHERE part_num = part_number AND

amt_in_bin > 0

ORDER BY bin_num

FOR UPDATE OF amt_in_bin;

bin_amt bins.amt_in_bin%TYPE;

total_so_far NUMBER(5) := 0;

amount_needed CONSTANT NUMBER(5) := 1000;

bins_looked_at NUMBER(3) := 0;

BEGIN

OPEN bin_cur(5469);

WHILE total_so_far < amount_needed LOOP

FETCH bin_cur INTO bin_amt;

EXIT WHEN bin_cur%NOTFOUND;

/* If we exit, there's not enough to *

* satisfy the order. */

bins_looked_at := bins_looked_at + 1;

IF total_so_far + bin_amt < amount_needed THEN

UPDATE bins SET amt_in_bin = 0

WHERE CURRENT OF bin_cur;

-- take everything in the bin

total_so_far := total_so_far + bin_amt;

ELSE -- we finally have enough

UPDATE bins SET amt_in_bin = amt_in_bin

- (amount_needed - total_so_far)

WHERE CURRENT OF bin_cur;

total_so_far := amount_needed;

END IF;

END LOOP;

CLOSE bin_cur;

INSERT INTO temp VALUES (NULL, bins_looked_at, '<- bins looked at');

COMMIT;

END;

-- Created on 2004-8-9 by ADMINISTRATOR

declare

--带有变量的Cursor

cursor crBooks(c_bookTitle varchar2) is

select *

from books a

where a.title like c_bookTitle||'%';

begin

for v_Books in crBooks('Oracle8') loop

dbms_output.put_line(v_Books.author1);

end loop;

end;

 
 
 
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