PL/SQL

--plsql
set serveroutput on;
begin
  dbms_output.put_line('Hello');
end;
 
  
--赋值  
declare  
  v_name varchar2(20);  
begin  
  v_name := 'myname';  
  dbms_output.put_line(v_name);  
end;  


--异常  
declare  
   v_num number :=0;  
begin  
   v_num := 2/v_num;  
   dbms_output.put_line(v_num);  
exception  
   --其他所有的情况  
   when others then  
   dbms_output.put_line('error');  
end;  


-- 变量声明
declare
  v_temp number(1);
  v_count binary_integer := 0;
  v_sal number(7,2) := 4000.00;
  v_pi constant number(3,2) := 3.14;
  v_valid boolean := false;
  v_name varchar2(20) not null := 'MyName';
begin
  -- boolean类型不能输出
  dbms_output.put_line('v_temp value:' || v_valid);
end;


-- 使用%type属性 变量的属性
declare
  v_empno number(4);
  v_empno2 emp.empno%type;
  v_empno v_empno2%type;
begin
  dbms_output.put_line('Test');
end;


-- Table变量类型 类似java里的数组
declare
  -- 定义一种新的类型 
  type type_table_emp_empno is table of emp.empno%type index by binary_integer;
  v_empnos type_table_emp_empno;
begin
  v_empnos(0) :=7369;
  v_empnos(-1) :=9999;
  v_empnos(2) :=7369;
  dbms_output.put_line(v_empnos(-1));
end


--Record变量类型 类似java里的class
declare
  type type_record_dept is record;
  (
    deptno dept.deptno%type,
    dname dept.dname%type,
    loc dept.loc%type
  );
  v_temp type_record_dept;
begin
  v_temp.deptno := 50;
  v_temp.dname := 'aaaa';
  v_temp.loc := 'bj';
end;


-- 使用%rowtype声明record变量
declare
  v_temp dept%rowtype
begin
  v_temp.deptno := 50;
  v_temp.dname := 'aaaa';
  v_temp.loc := 'bj';
end;


-- sql语句的运用
-- plsql里的sql语句必须返回一条且只有一条结果记录
declare
  v_ename emp.ename%type;
  v_sal emp.sal%type;
begin
  select ename, sal into v_ename, v_sal from emp where empno = 7369;
  dbms_output.put_line(v_ename || '  ' || v_sal);
end;

declare 
  v_ename emp%rowtype;
begin
  select * into v_emp from emp where empno = 7369;
  dbms_output.put_line(v_emp.ename);
end;

declare
  v_deptno dept.deptno%type := 50;
  v_dname dept.dname%type := 'aaa';
  v_loc dept.loc%type := 'bj';
begin
  insert into dept values (v_deptno, v_dname, v_loc);
  commit;
end

declare
  v_deptno emp.deptno%type := 50;
  v_count number;
begin
  -- （跟新了的条数）被影响
  update emp set sal = sal/2 where deptno = v_deptno;
  -- 1条记录被影响（最后产生了一个值）
  select deptno into v_deptno from emp where empno = 7369;
  -- 1条记录被影响（最后产生了一个值）
  select count(*) into v_count from emp;
  -- sql关键字 rowcount 刚刚影响的行数
  dbms_output.put_line(sql%rowcount || '条记录被影响');
  dbms_output.put_line(v_count || '条记录');
  commit;
end;

--ddl语句
begin
  execute immediate 'create table T (
    nnn varchar2(20) default ''aaa''
  )';
end;

-- if语句
declare 
  v_sal emp.sal%type;
begin
  select sal into v_sal from emp where empno = 7369;
  if (v_sal < 1200) then
    dbms_output.put_line('low');
  elsif (v_sal < 2000) then
    dbms_output.put_line('middle');
  else 
    dbms_output.put_line('high');
  end if
end;

-- 循环
declare
  i binary_integer := 1;
begin
  loop
    dbms_output.put_line(i);
    i := i + 1;
    exit when (i >= 11);
  end loop;
end;

begin
  for k in 1..10 loop
    dbms_output.put_line(k);
  end loop;
  for k in reverse 1..10 loop
    dbms_output.put_line(k);
  end loop;
end;

-- 异常
declare
  v_temp number(4);
begin
  select empno into v_temp from emp where deptno = 10;
exception
  when too_many_rows then
    dbms_output.put_line('to many');
  when others then
    dbms_output.put_line('error');
end;

declare
  v_temp number(4);
begin
  select empno into v_temp from emp where empno = 2222;
exception
  when no_data_found then
    dbms_output.put_line('empty');
end;

create table errorlog
(
  id number primary key,
  errcode number,
  errmsg varchar2(1024),
  errdate date
);

create sequence seq_errorlog_id start with 1 increment by 1;

declare
  v_deptno dept.deptno%type := 10;
  v_errcode number;
  v_errmsg varchar2(1024);
begin
  delete from dept where deptno = v_deptno;
  commit;
exception
  when others then
    rollback;
    v_errcode := SQLCODE;
    v_errmsg := SQLERRM;
    insert into errorlog values(seq_errorlog_id.nextval, v_errcode, v_errmsg, sysdate);
    commit;
end;


-- 游标
-- 只在查询结果集上的游标 RS
declare 
  cursor c is
    select * from emp;
  v_emp c%rowtype;
begin
  -- open时才去查询
  open c;
  -- 拿出c指的记录，放到v_emp中，游标自动往下移一条
  fetch c into v_emp;
  dbms_output.put_line(v_emp.ename);
  close c;
end;

-- 带循环的游标
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;
-- 如果dbms_output.put_line(v_emp.ename);在先，最后打出两便一样的结果

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;

-- c不用打开关闭fetch
declare 
  cursor c is
    select * from emp;
begin
  for v_emp in c loop
    dbms_output.put_line(v_emp.ename);
  end loop;
end;

-- 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;

--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;



-- 存储过程
create or replace procedure p
is
  cursor c is
    select * from emp for update;
begin
  for v_emp in c loop
    if (v_emp.deptno = 10) then
      update emp set sal = sal + 10 where current of c;
    elsif (v_emp.deptno = 20) then
      update emp set sal = sal + 20 where current of c;
    else
      update emp set sal = sal + 50 where current of c;
    end if;
  end loop;
  commit;
end;

exec p;

begin
  p;
end;

show error

-- 带参数的存储过程，没写in默认是in
create or replace procedure p
  (v_a in number, v_b number, v_ret out number, v_temp in out number)
is
begin
  if(v_a > v_b) then
    v_ret := v_a;
  else
    v_ret := v_b;
  end if;
  v_temp := v_temp + 1;
end;

declare
  v_a number := 3;
  v_b number := 4;
  v_ret number;
  v_temp number := 5;
begin
  p(v_a, v_b, v_ret, v_temp);
  dbms_output.put_line(v_ret);  
  dbms_output.put_line(v_temp);
end;  


-- 函数
create or replace function sal_tax
  (v_sal number)
  return number
is
begin
  if(v_sal < 2000) then
    return 0.10;
  elsif(v_sal < 2750) then
    return 0.15;
  else
    return 0.20;
  end if;
end;


--触发器
create table emp_log
(
  nuame varchar2(20),
  action varchar2(10),
  ation date
);

-- after在事件后触发触发器
create or replace trigger trig
  after insert or delete or update on emp
  -- after insert or delete or update on emp for each row
begin
  if inserting then
    insert into emp_log values (USER, 'insert', sysdate);
  elsif updating then
    insert into emp_log values (USER, 'update', sysdate);
  elsif deleting then
    insert into emp_log values (USER, 'delete', sysdate);
  end if;
end;

create or replace trigger tirg
  after update on dept
  for each row
begin
  update emp set deptno = :NEW.deptno where deptno = :OLD.deptno;
end;

update dept set deptno = 99 where deptno = 10;