Oracle游标总结

1.声明游标

declare
teacher_id number(5);
teacher_name varchar2(5);
teacher_title varchar2(50);
teacher_sex char(1);

cursor teacher_cur is
select tid,tiname,title,sex from teachers where tid<117;

2.打开游标

open 游标名;

declare
teacher_id number(5);
teacher_name varchar2(5);
teacher_title varchar2(50);
teacher_sex char(1);

cursor teacher_cur is
select tid,tiname,title,sex from teachers where tid<117;
open teacher_cur;

3.提取游标

fetch 游标名 into 变量列表

declare
teacher_id number(5);
teacher_name varchar2(5);
teacher_title varchar2(50);
teacher_sex char(1);

cursor teacher_cur is
select tid,tiname,title,sex from teachers where tid<117;
open teacher_cur;
fetch teacher_cur into tid,tinme,title,sex;

4.关闭游标

close 游标名

declare
teacher_id number(5);
teacher_name varchar2(5);
teacher_title varchar2(50);
teacher_sex char(1);

cursor teacher_cur is
select tid,tiname,title,sex from teachers where tid<117;
open teacher_cur;
fetch teacher_cur into tid,tinme,title,sex;
Loop
EXIT WHEN NOT teacher_cur%FUND;
IF teaher_sex = 'M' THEN
INSERT INTO MALE_TEACHERS(TID,TNAME,TITLE) VALUES();
ELSE
INSERT INTO FEMALE_TEACHERS(TID,TNAME,TITLE) VALUES(teacher_id,teacher_name,teacher_title);
END IF;
FETCH teacher_cur INTO teacher_id,teacher_name,teacher_title,teacher_sex;
END LOOP;
CLOSE teacher_cur;
END;

使用显示游标:

1):使用前用游标名%ISOPEN检查打开状态,只有值为TRUE是才可使用

2):使用游标每次都要用%NOTFUND,%FUND确认是否返回成功

3):提取游标时对应变量个数一致

4):必须关闭游标释放资源

1.%fund是否找到有效行,是则为true 否则是false

open teacher_cur;
fetch teacher_cur into teacher_id,teacher_name,teacher_title,teacher sex;
loop
exit when not teacher_cur%found;
end loop

　　SQL%fund

delete from teachers
where tid=teacher_id;
if SQL%found then
insert into success values(tid);
else
insert into fail values(tid);
end if;

2.%NOTFOUND

OPEN teacher_cur;
FETCH teacher_cur INTO teacher_id,teacher_name,teacher_title,teacher_sex;
LOOP
EXIT WHEN teacher_cur%NOTFOUND;
END LOOP

　　SQL%NOTFOUND

DELETE FROM TEACHERS
WHERE TID = teacher_id;
IF SQL%NOTFOUND THEN
INSERT INTO FALL VALUES(TID);
ELSE
INSERT INTO SUCCESS VALUES(TID);
END IF;

3.%ROWCOUNT

该属性记录了游标抽取过的记录行数,也可以理解为当前游标所在的行号,这个属性在循环判断中有效

LOOP
FETCH teacher_our INTO teacher_id,teacher_name,teacher_title,teacher_sex;
EXIT WHEN teacher_cur%ROWCOUNT=10;--只抽取10条记录
...
END LOOP;

用FOR语句控制游标的循环,系统隐含的定义了一个数据类型为%ROWCOUNT的记录,作为循环计数器,并将隐士的打开和关闭游标

FOR teacher_record in teacher_cur LOOP --teacher_record作为记录名,隐含的代开游标teacher_cur
INSERT INTO TEMP TEACHERS(TID,TNAME,TITLE,SEX) VALUES(teacher_record,tid,teacher_record,tname,teacher_record,title,teacher_record.sex);
END LOOP

4.%ISOPEN

... ...

5.参数话游标:

DECLARE
--定义游标是带上参数CURSOR_ID
CURSOR teacher_cur(CURSOR_id NUMBER) IS
SELECT TNAME,TITLE,SEX FROM TEACHERS WHERE TID=CURSOR_id;--使用参数
BEGIN
OPEN teacher_cur(my_tid);--带上参数
LOOP
FETCH teacher_cur INTO teacher_name,teacher_title,teacher_sex;
EXIT WHEN teacher_cur%NOTFOUND;
...
END LOOP;
CLOSE teacher_cur;
END;

特殊的游标类型

declare
r_emp emp%ROWTYPE;   --该类型为emp表中一行的类型
cursor c_emp is SELECT * FROM emp ;
BEGIN
OPEN c_emp;
LOOP
FETCH c_emp into r_emp;     --游标中查询出来的一行into进定义的变量r_emp中
EXIT WHEN c_emp%NOTFOUND;
dbms_output.put_line('员工姓名：' || r_emp.ename);
END LOOP;
CLOSE c_emp;
END;