同义词 索引 表分区

.同义词

grant create synonym to SCOTT
GRANT CREATE PUBLIC SYNONYM TO scott;


create synonym ee for SCOTT.emp
create  public synonym tt for SCOTT.emp


  grant select on emp to 具体的用户或者是模式
grant select on emp to public

可以访问了


5.索引
  索引作用：快速访问数据的途径，提高数据库的性能。
  SQL Server 索引：唯一索引（1）  复合索引  聚集索引（3） 非聚集索引 全文 索引  主键索引（2）。
 
  B数索引
 
 
  算法
  Bound mismatch: The generic method sort(List<T>) of type Collections is not applicable（合适） for the arguments (List<Student>). The inferred（推断） type Student is not a valid substitute（代用品） for the bounded parameter <T extends Comparable<? super T>>
  http://blog.youkuaiyun.com/xjyzxx/article/details/18465661
  http://www.cnblogs.com/pipi-style/p/4738072.html
  http://hexo.trity.cc/2015/08/24/Arrays.sort%E5%92%8CCollections.sort%E5%8C%BA%E5%88%AB/
  http://lib.youkuaiyun.com/article/datastructure/9282
 
 
6.表分区  


  create table orders
  (
    order_id number,
    order_date date,
    order_total number
  )
partition by range(order_date)
(
   partition p1 values less than (to_date('2005-01-01','yyyy-mm-dd')),
   partition p2 values less than (maxvalue)
   
)

--添加数据
insert into orders values(1,sysdate,100)


select * from orders  partition(p2)

SELECT table_name,partition_name
         FROM user_tab_partitions
     WHERE table_name=UPPER('orders');
 

create table intervalOrders
          partition by range(order_date)
        interval(numtoyminterval(1,'YEAR'))
        (partition P1 values less than (to_date('2015-01-01','yyyy/mm/dd')))
        as select  * from  orders;   
   
   insert into intervalOrders values(2,to_date('2010-01-01','yyyy/mm/dd'),200)
   
   select * from intervalOrders partition(SYS_P42)
   
   
   insert into intervalOrders values(3,sysdate,300)