PLSQL编程

首先

SQL> set serveroutput on;

基本语法

create or replace procedure [名称](变量名 in/out 类型) is
[定义变量]
begin
    [语句]
end；
/

循环语句实例：打印99乘法表

create or replace procedure chengfabiao is
begin
  for i in 1 .. 9 loop
    for j in 1 .. 9 loop
      dbms_output.put(' '||i||' x '||j||' = '||i*j); ----put不会换行
    end loop;
    dbms_output.put_line(''); ----put_line可以换行
    end loop;
end;
/

控制语句/游标实例：输出工资水平

create or replace procedure gongzishuiping is
 cursor cur_emp is ----游标必须和循环语句联合使用
   select * from emp;
begin
  for x in cur_emp loop ----或者case when…then end case；
    if x.sal between 700 and 1400 then
      dbms_output.put_line(x.empno||' '||x.ename||' '||x.sal||' '||'laji');
    elsif x.sal between 1401 and 2000 then
      dbms_output.put_line(x.empno||' '||x.ename||' '||x.sal||' '||'yiban');
    elsif x.sal between 2001 and 4000 then
      dbms_output.put_line(x.empno||' '||x.ename||' '||x.sal||' '||'bucuo');
    end if;
  end loop;
end;
/

动态游标

DECLARE
    teacher_id NUMBER(5);
    teacher_name VARCHAR2(50);
    teacher_title VARCHAR2(50);
    teacher_sex char(1);  ---定义变量存放teachers表中的内容
CURSOR teacher_cur IS
    SELECT TID,TNAME,TITLE,SEX
    FROM TEACHERS
    WHERE TID<117;        ---选择号码小于117的数据
BEGIN
OPEN teacher_cur;         ---打开游标
    FETCH teacher_cur INTO teacher_id,teacher_name,teacher_title,teacher_sex;
                          ---将！第一行！数据存入变量中，游标后移。在循环外相当于启动循环
    LOOP
      EXIT WHEN NOT teacher_cur%FOUND;   ---如果游标到尾则结束
      IF teacher_sex='M' THEN            
         INSERT INTO MALE_TEACHERS(TID,TNAME,TITLE)
             VALUES(teacher_id,teacher_name,teacher_tile);
      ELSE
         INSERT INTO FRMALE_TEACHERS(TID,TNAME,TITLE)
             VALUES(teacher_id,teacher_name,teacher_title);
      END IF;            ---条件控制实现男女分离
      FETCH teacher_cur INTO teacher_id,teacher_name,teacher_title,teacher_sex;  
                         ---游标移动到下一行，在循环里
    END LOOP;
CLOSE teacher_cur;       ---关闭游标
END;

/*按照sal=2000分类，显示员工编号，姓名，工资，部门编号。自己想的实例*/
DECLARE 
    v_ename VARCHAR2(10);
    v_empno NUMBER(4);
    v_deptno NUMBER(2);
    v_sal NUMBER(7,2);
CURSOR cur_emp IS
    SELECT empno,ename,sal,deptno FROM emp;
BEGIN
OPEN cur_emp;
     FETCH cur_emp INTO v_empno,v_ename,v_sal,v_deptno;
     LOOP 
           EXIT WHEN NOT cur_emp%FOUND;
     IF v_sal >= 2000  THEN
       INSERT INTO 
           niubi(IEMPNO,IENAME,ISAL,IDEPTNO)
           VALUES(v_empno,v_ename,v_sal,v_deptno);
     ELSE 
       INSERT INTO
           laji(IEMPNO,IENAME,ISAL,IDEPTNO)
           VALUES(v_empno,v_ename,v_sal,v_deptno);
     END IF;
     FETCH cur_emp INTO v_empno,v_ename,v_sal,v_deptno;
     END LOOP;
CLOSE cur_emp;
END;

函数调用实例：工资等级分类统计

CREATE OR REPLACE FUNCTION count_num  --创建函数
(daxiao in VARCHAR2)         --指定 输入变量 变量类型和某个变量一致
        return NUMBER                 --指定返回值的类型
AS
        out_num NUMBER;
BEGIN
        IF daxiao='>' THEN
             SELECT count(*) INTO out_num
        FROM emp
        WHERE sal>=2000;
        ELSE
              SELECT count(*) INTO out_num
        FROM emp
        WHERE sal<2000;
        END IF;
        RETURN(out_num);
END count_num;
/

DECLARE         --存储过程调用函数count_num
    da_num NUMBER;
    xiao_num NUMBER;
BEGIN
    da_num:=count_num('>');
    dbms_output.put_line(da_num);
    xiao_num:=count_num('<');
    dbms_output.put_line(xiao_num);
END;
/

触发器实例：对emp进行增删改时记录操作类型和实践

CREATE OR REPLACE TRIGGER tr_log
   AFTER INSERT OR UPDATE OR DELETE ON emp
   FOR each row  --对每行
DECLARE
   info VARCHAR2(10);
BEGIN
   IF inserting THEN
     info:='INSERT';
   ELSIF updating THEN
     info:='UPDATE';
   ELSE
     info:='DELETE';
   END IF;
   INSERT INTO SQL_INFO VALUES(info,SYSDATE);
END tr_log;