oracle常用经典SQL查询

dn001 2010-03-05 15:29:57

　　25. 查询表空间的碎片程度

　　select tablespace_name,count(tablespace_name) from dba_free_space group by tablespace_name

　　having count(tablespace_name)>10;

　　alter tablespace name coalesce;

　　alter table name deallocate unused;

　　create or replace view ts_blocks_v as

　　select tablespace_name,block_id,bytes,blocks,'free space' segment_name from dba_free_space

　　union all

　　select tablespace_name,block_id,bytes,blocks,segment_name from dba_extents;

　　select * from ts_blocks_v;

　　select tablespace_name,sum(bytes),max(bytes),count(block_id) from dba_free_space

　　group by tablespace_name;

　　26。查询有哪些数据库实例在运行

　　select inst_name from v$active_instances;

　　===========================================================

　　######### 创建数据库----look $ORACLE_HOME/rdbms/admin/buildall.sql #############

　　create database db01

　　maxlogfiles 10

　　maxdatafiles 1024

　　maxinstances 2

　　logfile

　　GROUP 1 ('/u01/oradata/db01/log_01_db01.rdo') SIZE 15M,

　　GROUP 2 ('/u01/oradata/db01/log_02_db01.rdo') SIZE 15M,

　　GROUP 3 ('/u01/oradata/db01/log_03_db01.rdo') SIZE 15M,

　　datafile 'u01/oradata/db01/system_01_db01.dbf') SIZE 100M,

　　undo tablespace UNDO

　　datafile '/u01/oradata/db01/undo_01_db01.dbf' SIZE 40M