SQL随记(一)

1.关于define表示定义

2.sql%rowcount用于记录修改的条数,必须放在一个CUD语句后面执行,无法在select中使用。

3.两种调用过程的关键字:exec和call

 两者区别:

(1)exec是sqlplus命令,只能在sqlplus中使用;call为SQL命令,没有限制. 

(2)存储过程没有参数时,exec可以直接跟过程名(可以省略()),但call则必须带上()

4.复制表数据,用where 1=0等;

5.关于&和&&的区别:看http://blog.csdn.net/studyvcmfc/article/details/7055258;

主要区别在与:

&username和&&usernae都会在sqlplus执行的时候,会提示你输入一个username对应的值。

但&输入一次后,下次遇到还要继续输入;而&&输入一次后,下次遇到会默认选择上一次输入的内容。

6.授权:grant

回收权限:remvoke 

define numrows=10000000  --definde 表示定义变量
drop table big_table purge;

create table big_table
as
select rownum id, OWNER, OBJECT_NAME, SUBOBJECT_NAME, OBJECT_ID,
DATA_OBJECT_ID, OBJECT_TYPE, CREATED, LAST_DDL_TIME, TIMESTAMP,
STATUS, TEMPORARY, GENERATED, SECONDARY, NAMESPACE, EDITION_NAME
  from all_objects
 where 1=0
/

alter table big_table nologging;

declare
  l_cnt number;
  l_rows number := &numrows;
begin
  insert /*+ append */
  into big_table
  select rownum id, OWNER, OBJECT_NAME, SUBOBJECT_NAME, OBJECT_ID,
  DATA_OBJECT_ID, OBJECT_TYPE, CREATED, LAST_DDL_TIME, TIMESTAMP,
  STATUS, TEMPORARY, GENERATED, SECONDARY, NAMESPACE, EDITION_NAME
  from all_objects
  where rownum <= &numrows; --numrows的值为10000000
  --
  l_cnt := sql%rowcount;--sql%rowcount用于记录修改的条数
  commit;
  while (l_cnt < l_rows)
  loop
    insert /*+ APPEND */ into big_table
    select rownum+l_cnt,OWNER, OBJECT_NAME, SUBOBJECT_NAME, OBJECT_ID,
    DATA_OBJECT_ID, OBJECT_TYPE, CREATED, LAST_DDL_TIME, TIMESTAMP,
    STATUS, TEMPORARY, GENERATED, SECONDARY, NAMESPACE, EDITION_NAME
    from big_table a
    where rownum <= l_rows-l_cnt;
    l_cnt := l_cnt + sql%rowcount;
    commit;
  end loop;
end;
/

alter table big_table add constraint
big_table_pk primary key(id);

exec dbms_stats.gather_table_stats( user, 'BIG_TABLE', estimate_percent=> 1);--exec就是调用存储过程,1但是exec是sqlplus命令,只能在sqlplus中使用;call为SQL命令,没有限制. 2存储过程没有参数时,exec可以直接跟过程名(可以省略()),但call则必须带上(). 

  

connect / as sysdba
define username=eoda
define usernamepwd=foo
create user &&username identified by &&usernamepwd;
grant dba to &&username;
grant execute on dbms_stats to &&username;--给dbms_stats过程授予权限
grant select on V_$STATNAME to &&username;--赋予查询权限
grant select on V_$MYSTAT   to &&username;
grant select on V_$LATCH    to &&username;
grant select on V_$TIMER    to &&username;
conn &&username/&&usernamepwd

  

原文地址:https://www.cnblogs.com/lirenzhujiu/p/7019041.html