一. 使用for循環遊標：遍歷全部職位為經理的雇員

1. 定義遊標(遊標就是一個小集合)

2. 定義遊標變量

3. 使用for循環遊標

declare
  -- 定義遊標c_job
  cursor c_job is
    select empno, ename, job, sal from emp where job = ‘MANAGER‘;
    
  -- 定義遊標變量c_row
  c_row c_job%rowtype;
begin
  -- 循環遊標，用遊標變量c_row存循環出的值
  for c_row in c_job loop
    dbms_output.put_line(c_row.empno || ‘-‘ || c_row.ename || ‘-‘ ||
                         c_row.job || ‘-‘ || c_row.sal);
  end loop;
end;

二. fetch遊標：遍歷全部職位為經理的雇員

使用的時候必須明白的打開和關閉

declare
  --定義遊標c_job
  cursor c_job is
    select empno, ename, job, sal from emp where job = ‘MANAGER‘;

  --定義遊標變量c_row
  c_row c_job%rowtype;
begin
  open c_job;
  loop
    --提取一行數據到c_row
    fetch c_job into c_row;
    
    --判讀是否提取到值。沒取到值就退出
    exit when c_job%notfound;
    dbms_output.put_line(c_row.empno || ‘-‘ || c_row.ename || ‘-‘ ||
                         c_row.job || ‘-‘ || c_row.sal);
  end loop;
  
  --關閉遊標
  close c_job;
end;

三. 使用遊標和while循環：遍歷全部部門的地理位置

--3,使用遊標和while循環來顯示全部部門的的地理位置（用%found屬性）
declare
  --聲明遊標
  cursor csr_TestWhile is select loc from dept;

  --指定行指針
  row_loc csr_TestWhile%rowtype;
begin
  open csr_TestWhile;
  --給第一行數據
  fetch csr_TestWhile into row_loc;
  
  --測試是否有數據，並運行循環
  while csr_TestWhile%found loop
    dbms_output.put_line(‘部門地點：‘ || row_loc.LOC);
    --給下一行數據
    fetch csr_TestWhile into row_loc;
  end loop;
  close csr_TestWhile;
end;

四. 帶參的遊標：接受用戶輸入的部門編號

declare
  -- 帶參的遊標
  cursor c_dept(p_deptNo number) is
    select * from emp where emp.deptno = p_deptNo;
    
  r_emp emp%rowtype;
begin
  for r_emp in c_dept(20) loop
    dbms_output.put_line(‘員工號：‘ || r_emp.EMPNO || ‘員工名：‘ 
                         || r_emp.ENAME || ‘工資：‘ || r_emp.SAL);
  end loop;
end;

五. 加鎖的遊標：對全部的salesman添加傭金500

declare
  --查詢數據，加鎖(for update of)
  cursor csr_addComm(p_job nvarchar2) is
    select * from emp where job = p_job for update of comm;
  r_addComm emp%rowtype;
  commInfo  emp.comm%type;
begin
  for r_addComm in csr_addComm(‘SALESMAN‘) loop
    commInfo := r_addComm.comm + 500;
    
    --更新數據(where current of)
    update emp set comm = commInfo where current of csr_addComm;
  end loop;
end;

declare
  cursor crs_testComput is
    select * from emp order by hiredate asc;
    
  --計數器
  top_two      number := 2;
  r_testComput crs_testComput%rowtype;
begin
  open crs_testComput;
  fetch crs_testComput into r_testComput;
  while top_two > 0 loop
    dbms_output.put_line(‘員工姓名：‘ || r_testComput.ename ||
                         ‘ 工作時間：‘ || r_testComput.hiredate);
    --計速器減1
    top_two := top_two - 1;
    fetch crs_testComput into r_testComput;
  end loop;
  close crs_testComput;
end;

declare
  cursor crs_upadateSal is
    select * from emp for update of sal;
  r_updateSal crs_upadateSal%rowtype;
  salAdd      emp.sal%type;
  salInfo     emp.sal%type;
begin
  for r_updateSal in crs_upadateSal loop
    salAdd := r_updateSal.sal * 0.2;
    if salAdd > 300 then
      salInfo := r_updateSal.sal;
      dbms_output.put_line(r_updateSal.ename || ‘:  加薪失敗。‘ ||
                           ‘薪水維持在：‘ || r_updateSal.sal);
    else
      salInfo := r_updateSal.sal + salAdd;
      dbms_output.put_line(r_updateSal.ENAME || ‘:  加薪成功.‘ ||
                           ‘薪水變為：‘ || salInfo);
    end if;
    update emp set sal = salInfo where current of crs_upadateSal;
  end loop;
end;

declare
  cursor crs_caseTest is
    select * from emp for update of sal;

  r_caseTest crs_caseTest%rowtype;
  salInfo    emp.sal%type;
begin
  for r_caseTest in crs_caseTest loop
    case
      when r_caseTest.deptno = 10 THEN
        salInfo := r_caseTest.sal * 1.05;
      when r_caseTest.deptno = 20 THEN
        salInfo := r_caseTest.sal * 1.1;
      when r_caseTest.deptno = 30 THEN
        salInfo := r_caseTest.sal * 1.15;
      when r_caseTest.deptno = 40 THEN
        salInfo := r_caseTest.sal * 1.2;
    end case;
    update emp set sal = salInfo where current of crs_caseTest;
  end loop;
end;

九. 異常處理：數據回滾

set serveroutput on;
declare
  d_name varchar2(20);
begin
  d_name := ‘developer‘;
  
  savepoint A;
  insert into DEPT values (50, d_name, ‘beijing‘);
  savepoint B;
  insert into DEPT values (40, d_name, ‘shanghai‘);
  savepoint C;
  
  exception when others then
    dbms_output.put_line(‘error happens‘); 
	  rollback to A;
  commit;
end;
/

十. 基本指令：

set serveroutput on size 1000000 format wrapped; --使DBMS_OUTPUT有效,並設置成最大buffer,防止"吃掉"最前面的空格
set linesize 256; --設置一行能夠容納的字符數
set pagesize 50; --設置一頁有多少行數
set arraysize 5000; --設置來回數據顯示量,這個值會影響autotrace時一致性讀等數據
set newpage none; --頁和頁之間不設不論什麽間隔
set long 5000; --LONG或CLOB顯示的長度
set trimspool on; --將SPOOL輸出中每行後面多余的空格去掉
set timing on; --設置查詢耗時
col plan_plus_exp format a120; --autotrace後explain plan output的格式
set termout off; --在屏幕上暫不顯示輸出的內容,為以下的設置sql做準備
alter session set nls_date_format=‘yyyy-mm-dd hh24:mi:ss‘; --設置時間格式

以下的語句一定要在Command Window裏面才幹打印出內容

set serveroutput on;
begin 
dbms_output.put_line(‘hello!‘);
end;
/

oracle存儲過程的使用