oracle常用操作

1 验证表统计信息

begin
DBMS_STATS.GATHER_TABLE_STATS (
ownname => 'owner_name',
tabname => 'table_name',
estimate_percent => 100
);
end;

2 用table2更新table1

--根据id(有唯一约束的字段)将table2的字段更新到table1
update (select a.f1 a1, a.f2 a2, b.f1 b1, b.f2 b2
from table1 a, table2 b where a.id = b.id)
set a1 = b1, a2 = b2;

3 添加/删除主键

alter table table_name add constraint table_name_pk primary key(id);
alter table table_name drop constraint table_name_pk;

4 启用/禁用触发器

alter trigger trigger_name enable;
alter trigger trigger_name disable;

5查询rownum在10-20的行

select * from
(select t.*,rownum r from test t where rownum <= 20) where r >10;

select t.*,rownum r from test t where rownum <= 20
minus
select t.*,rownum r from test t where rownum <= 10;

6 用户授权

--授予用户选择和删除的权限
grant select,delete on table_name to user_name;

7 查看建表语句

select dbms_metadata.get_ddl('TABLE', 'T1') from dual;  -- 查看T1的ddl