Oracle学习笔记6

一． 游标
1） --do while 循环
Declare
Cursor c is select * from emp;

V_emp c%rowtype;

Begin

Open c;

loop

Fetch c into v_emp;

Exit when (c%notfound);

Dbms_output.put_line(v_emp.ename);

End loop;

Close c;

End;

2） --while 循环
Declare
Cursor c is select * from emp;

V_emp c%rowtype;

Begin

Open c;

Fetch c into v_emp;

While (c%found) loop

Dbms_output.put_line(v_emp.ename);

Fetch c into v_emp;
End loop;

Close c;

End;

3） --for 循环（推荐）
Declare
Cursor c is select * from emp;

Begin

For v_emp in c loop

Dbms_output.put_line(v_emp.ename);

End loop;

End;

4） -- 带参数的游标
Declare
Cursor c(v_deptno emp.deptno%type, v_job emp.job%type) is

select ename, sal from emp where deptno = v_deptno and job = v_job;
Begin

For v_temp in c(30, ‘clerk’) loop

Dbms_output.put_line(v_temp.ename);

End loop;

End;

5） -- 可更新的游标
Declare

Cursor c is

Select * from emp for update ;

Begin

For v_temp in c loop

If(v_temp.sal < 2000) then

Update emp set sal = sal * 2 where current of c ;

Elsif (v_temp.sal = 5000) then

Delete from emp where current of c;

End if;

End loop;

Commit;

End;

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