Oracle 小知识点（备忘）

--①系统变更号
--获取数据时间插入时间  ora_rowscn返回行最近一次修改的scn.
select scn_to_timestamp(ora_rowscn),tt.* from tt;
--scn与timestamp转换
select timestamp_to_scn(sysdate) from dual ;
select to_char(scn_to_timestamp(timestamp_to_scn(sysdate)),'yyyy-mm-dd hh24:mi:ss') from dual ;


--②wm_concat 与listagg
/*wm_concat就存在10g 11g  之前用自定义函数 strcat
11g 及之后存在listagg
wm_concat 可以去重  listagg 可以排序*/
select tt.id,
       wm_concat(distinct tt.name) name1,
       listagg(tt.name, ';') within group(order by name) name2
  from tt
 group by tt.id;
 
 
--③计算表达式
select dbms_aw.eval_number('20*20') from dual ;
  例子计算1-10  合为10的组合  跟connect_by_path() 结合使用


with t as
 (select 1 a from dual  union all
  select 2 a from dual  union all
  select 3 a from dual  union all
  select 4 a from dual  union all
  select 5 a from dual  union all
  select 6 a from dual  union all
  select 7 a from dual  union all
  select 8 a from dual  union all
  select 9 a from dual),
  t1 as (
  select t.*,
         dbms_aw.eval_number(substr(sys_connect_by_path(a, '+'), 2)) dd,
         substr(sys_connect_by_path(a, '+'), 2) cc
    from t
  connect by nocycle a > prior a 
  and level <=4
  )
        
  select * from t1 where dd =10
;


--④ 迁移数据是 禁用/恢复 约束
ALTER TABLE test_phone_tab disable constraint test_phone_pk;
ALTER TABLE test_phone_tab enable constraint test_phone_pk; 


--⑤分区可以有默认分区 （自己思维定式 未仔细想过）
   列表可存多个值

create table t_partition_list (id number,name varchar2(50))   

 partition by list(id)
 (    partition t_list_p1 values (1,2,3,4,5,6,7,8,9) ,    --可以多个值
   partition t_list_p2 values (10,11,12,13,14,15,16,17,18,19) ,  
     partition t_list_p3 values (20,21,22,23,24,25,26,27,28,29),  
      partition t_list_pd values (default) ）;   --可以有默认分区  需要制定
 /*****范围分区  < maxvalue  默认分区 ***/    

  /*****哈希分区  本来就是随机分配分区 ***/  

 
      insert into  t_partition_list
      select level+15,'name'||level
       from dual connect by level <26
      select * from t_partition_list partition (t_list_p2)    ;  
      select * from t_partition_list partition (t_list_p3)     ; 
      select * from t_partition_list partition (t_list_pd);

--oracle 子分区模板  subpartition template  add at 2016.08.25
create table csdn_sub_part
(
id number,
grade varchar2(10),
sal number
)
partition by list (grade) subpartition by range (sal)
subpartition template   --此处关键字
(
subpartition subpart_20 values less than (20) ,
subpartition subpart_40 values less than (40) ,
subpartition subpart_60 values less than (60) ,
subpartition subpart_80 values less than (80) ,
subpartition subpart_100 values less than (100) ,
subpartition subpart_other values less than (maxvalue)   --range 默认分区
)
(
partition p_01 values ('A','B'),
partition p_02 values ('C','D','E'),
partition p_03 values (default)   --list 默认分区
)


--增加住分区 利用子分区模板
alter table  csdn_sub_part add  partition p_04 values ('F');
------------- ora-14233：在default分区存在时无法添加分区---
/*
先删除default分区 （备份）
创建新的子分区   默认分区
重新insert进表  分区存储
*/

create table zz_dl as
select * from csdn_sub_part where 1=0;
alter table csdn_sub_part  exchange partition p_03 with table  zz_dl;
--丫的组合分区 无法exchange 
insert into zz_dl
select * from csdn_sub_part partition (p_03);
alter table csdn_sub_part drop partition p_03;

alter table csdn_sub_part add partition p_03 values ('F');
--ora-14020:不能指定表分区的物理属性  values 写成 value

alter table csdn_sub_part add partition p_default  values (default);

insert into csdn_sub_part
select * from zz_dl;
commit;

--⑥JOB执行多个任务

what      => 'sp_emp_01;sp_emp_02;'

或者(貌似一个意思)

what      => '
begin
sp_emp_01;
sp_emp_02;
end;'

⑦ sqlplus c 和 edit 这两个功能 

c/t/t1 记录上次执行的命令 具体 c/t/t1啥意思位置
edit 编辑上次执行的命令 修改后可 c/t/t1查询

⑧、子查询 结果显示为cursor
select d.deptno,
       d.dname,
       cursor (select e.empno, e.ename, e.sal
                 from emp e
                where d.deptno = e.deptno) as details
  from dept d

⑨、普通表转变成分区表
  ① 创建一个新的分区表 insert into 分区表
  ② 穿件一个新的分区表 创建分区对应的几个基础表  exchange 语句
  ③ 在线重新定义 DBMS_REDEFINITION
--在线重新定义（普通表边分区表）
--  ① 创建一个新的分区表 insert into 分区表
--  ② 穿件一个新的分区表 创建分区对应的几个基础表  exchange 语句
--  ③ 在线重新定义 DBMS_REDEFINITION

--① 创建一个新的分区表 insert into 分区表
create table comm_table
(id number,
 name varchar2(20),
 data_date varchar2(8));
 

select * from comm_table;

insert /*+append*/
into comm_table nologging
  select level, level || 'name', '20161201'
    from dual
  connect by level <= 100000;
   commit;

select * from comm_table;

create table part_table
(id number,
 name varchar2(20),
 data_date varchar2(8))
partition by list (data_date)
 (partition part_20161201 values ('20161201') tablespace users,
 partition part_20161202 values ('20161202') tablespace users,
 partition part_20161203 values ('20161203') tablespace users
 )
;

insert/*+append*/ into part_table nologging
select /*+parallel(a,4)*/  * from comm_table a;

select * from part_table partition(part_20161203);


--② 穿件一个新的分区表 创建分区对应的几个基础表  exchange 语句
create table part_table2
(id number,
 name varchar2(20),
 data_date varchar2(8))
partition by list (data_date)
 (partition part_20161201 values ('20161201') tablespace users,
 partition part_20161202 values ('20161202') tablespace users,
 partition part_20161203 values ('20161203') tablespace users
 );
 
 alter table part_table2 exchange partition part_20161201 with table comm_table;
 --ora-14099 未指定分区限定表中的所有行
 create table comm_table_1201
 as
 select /*+parallel(a,4)*/ * from  comm_table a where a.data_date='20161201';
 
 create table comm_table_1202
 as
 select /*+parallel(a,4)*/ * from  comm_table a where a.data_date='20161202';

 create table comm_table_1203
 as
 select /*+parallel(a,4)*/ * from  comm_table a where a.data_date='20161203';
 select * from comm_table_1202;
 
  alter table part_table2 exchange partition part_20161201 with table comm_table_1201;
  alter table part_table2 exchange partition part_20161202 with table comm_table_1202;
  alter table part_table2 exchange partition part_20161203 with table comm_table_1203;
  select * from part_table2;
  select * from comm_table_1201;
  
--③ 在线重新定义 DBMS_REDEFINITION
--源表
create table demo as select empno,ename,sal,deptno from scott.emp;
--没主键不行啊
alter table demo add constraint demo_pk primary key(empno);

create index demo_idx on demo(ename);

--检测重定义合理性
begin
   DBMS_REDEFINITION.CAN_REDEF_TABLE('logminer', 'demo');
end;
--中间表
create table demo_tmp
 partition by range(deptno)
 (
  partition p1 values less than (11),
   partition p2 values less than (21),
  partition p3 values less than (31)
  )
  as
 select * from demo where 1=2;

--执行在线重定义
 BEGIN
    DBMS_REDEFINITION.START_REDEF_TABLE('LOGMINER', 'DEMO', 'DEMO_TMP');
 END;
 
 select object_id,object_name,object_type,status from user_objects;
 我们注意到Oracle新建了两张表RUPD$_DEMO和MLOG$_DEMO，
 其实Oracle在线重定义是通过物化视图的LOG来实现的。做完这一步后，在中间表中也有了相同的数据
 select * from DEMO;
 select * from DEMO_TMP;

--结束在线重定义
begin
    DBMS_REDEFINITION.FINISH_REDEF_TABLE('LOGMINER', 'DEMO', 'DEMO_TMP');
end;

select * from DEMO;
--成功
/**************结语************/
/*
     需要创建主键，（索引可无），创建中间表，实用性不太好，记住这个功能
*/

⑩、pl/sql的data genertor
选择 用户，表之后，在data中选择想要的数据，生成随机数不错
[图片]

⑩①、归档日志满了
sqlplus /nolog
connect /as sysdba
select * from V$FLASH_RECOVERY_AREA_USAGE;
select sum(percent_space_used)*3/100 from v$flash_recovery_area_usage;
ALTER SYSTEM SET DB_RECOVERY_FILE_DEST_SIZE=8g;
show parameter recover;

rman
connect target sys/sys_passwd
DELETE ARCHIVELOG ALL COMPLETED BEFORE 'SYSDATE-7';