oracle基本語法

-- 表
create table test (names varchar2(12),
                   dates date,
                   num   int,
                   dou   double);
-- 視圖
create or replace view vi_test as
select * from test;

-- 同義詞
create or replace synonym aa
for dbusrcard001.aa;

-- 存儲過程
create or replace produce dd(v_id in employee.empoy_id%type)
as
begin
   
end
dd;

-- 函數
create or replace function ee(v_id in employee%rowtype) return varchar(15)
is
var_test varchar2(15);
begin
  return var_test;
exception when others then
   
end

-- 三種觸發器的定義
create or replace trigger ff
alter delete
on test
for each row
declare
begin
   delete from test;
   if sql%rowcount < 0 or sql%rowcount is null then
      rais_replaction_err(-20004,"錯誤")
   end if
end


create or replace trigger gg
alter insert
on test
for each row
declare
begin
   if :old.names = :new.names then
      raise_replaction_err(-2003,"編碼重複");
   end if
end


create or replace trigger hh
for update
on test
for each row
declare
begin
  if updating then
     if :old.names <> :new.names then
 reaise_replaction_err(-2002,"關鍵字不能修改")
     end if
  end if
end 

-- 定義遊標
declare
   cursor aa is
      select names,num from test;
begin
   for bb in aa
   loop
        if bb.names = "ORACLE" then
        
        end if
   end loop;
   
end

-- 速度優化，前一語句不後一語句的速度快幾十倍
select names,dates 
from test,b
where test.names = b.names(+) 
 and b.names is null 
 and b.dates > date(''2003-01-01'',''yyyy-mm-dd'')

 
select names,dates
from test 
where names not in ( select names  from b
                      where dates > to_date(''2003-01-01'',''yyyy-mm-dd''))
                       

-- 查找重複記錄
select names,num 
from test 
where rowid != (select max(rowid) 
                 from test b 
                where b.names = test.names and
                      b.num = test.num)


-- 查找表TEST中時間最新的前10條記錄
select * from (select * from test order by dates desc) where rownum < 11

-- 序列號的產生
create sequence row_id
minvalue 1
maxvalue 9999999999999999999999
start with 1
increment by 1

insert into test values(row_id.nextval,....)