oracle的一些备用查询语句

'--建表语句
CREATE TABLE ac_rule_product (
id number(20) NOT NULL PRIMARY KEY ,
product_type varchar2(255) NOT NULL ,
product_name varchar2(255) NULL ,
login_type varchar2(255) NOT NULL ,
enable number(1) NOT NULL
)
--添加索引
create UNIQUE index product_type on ac_rule_product(product_type,login_type)

--添加主键
alter table ac_type_login add constraint yy primary key(id，type_key);

--添加级联删除
ON DELETE CASCADE

-- 添加注释
comment on column AC_RULE_PRODUCT.id
is '唯一ID';
comment on column AC_RULE_PRODUCT.product_type
is '渠道类型';

--添加外键
alter table AC_RULE_PRODUCT
add constraint AC_RULE_PRODUCT_IBFK_2 foreign key (LOGIN_TYPE)
references AC_TYPE_LOGIN (TYPE_KEY) on delete cascade;

--创建函数trunc
create or replace function trunc
(v_date in TIMESTAMP)
return timestamp
as
v_i TIMESTAMP;

begin

SELECT date_format(v_date,'%Y-%m-%d') into v_i;

return v_i;
end;

--修改字段
alter table ac_sys_log modify (RECORD_TIME date);

--查询当前时间
select sysdate from dual

--创建序列
create sequence SEQ_AC_OPT_LOG_ID
minvalue 1
maxvalue 9999999999999999999999999999
start with 1
increment by 1
cache 20;

--创建触发器
CREATE OR REPLACE TRIGGER "TRI_AC_OPT_LOG" -- (自定义触发器名称)
before insert
on ac_opt_log
for each row
begin
select SEQ_AC_OPT_LOG_ID.nextval into :new.id from dual; -- (需要自增的字段)
end;
'