Oracle使用REF 动态游标

1：定义REF动态游标类型

TYPE <类型名> IS REF CURSOR

RETURN <返回类型>;

 声明REF动态游标

<游标名>  <类型名>

打开REF动态游标

OPEN <游标名> FOR <查询语句>

2：REF动态游标的分类

 主要分为两类，强类型和弱类型的，强类型的为带有RETURN语句的REF动态游标，弱类型为不带有RETURN语句的REF动态游标,弱类型的动态游标可以与任何查询语句匹配，但是强类型的动态游标只能与特定的查询语句匹配。

强类型REF动态游标实例：

DECLARE

   TYPE refcur_t IS REF CORSOR

  RETURN employees%ROWTYPE;

  refcur refcur_t;

 v_emp employees%ROWTYPE;

BEGIN

 OPEN refcur FOR

 SELECT * FROM employees;

 LOOP

    FETCH refcur INTO v_emp;

    EXIT WHEN refcur%NOTFOUND;

    dbms_output.put_line(refcur % ROWCOUNT || ' ' || v_emp.name);

 END LOOP;

 CLOSE refcur;

END;

弱类型REF动态游标实例一：

DECLARE

   TYPE refcur_t IS  REF CURSOR;

    refcur   refcur_t;

    e_id  NUMBER;

    e_name  VARCHAR2(50);

BEGIN

   OPEN refcur FOR

   select id, name FROM employees;

   FETCH refcur INTO e_id, e_name;

  WHILE refcur%FOUND LOOP

          DBMS_OUTPUT.PUT_LINE('#' || e_id  ||  ':'  || e_name);

    FETCH refcur  INTO e_id, e_name;

  END LOOP;

  CLOSE refcur;

END;

弱类型REF动态游标实例二：根据用户的输入查询部门表或者员工信息表

DECLARE

TYPE refcur_t IS REF CURSOR;

refcur refcur_t;

pid NUMBER;

p_name VARCHAR2(50);

selection VARCHAR2(1) := UPPER(SUBSTR(‘&tab’, 1, 1));

BEGIN

IF selection = ‘E’ then

 OPEN refcur FOR

       select id, name from employees;

 dbms_output.put_line('====员工信息======');

elseif selection = 'D' then

   open refcur for

           select department_id, department_name  from departments;

    dbms_output.put_line('=====部门信息========')'

 else

    dbms_output.put_line('请输入员工信息(E) 或者部门信息(D)');

    return;

end if;

fetch refcur into p_id, p_name;

while refcur %FOUND LOOP

      dbms_output.put_line('#' ||  p_id  || ':' || p_name);

      fetch refcur into p_id, p_name;

 end loop;

 close refcur;

end;