1. tablespace,segment,extent,block
tablespace: database logical is divided into more tablesapces.
segment: a special storage structure(table,index),span more datafiles
extents:allocate unit
block: use unit,write/read unit
db_block_size, default block size. standand block size,system tablespace use.
db_nk_block_size,not standand block size, other tablespace
Any given tablespace will have a consistent block size
any given segment(which is contained in a tablespace) will consist of blocks of exactly the same size
head,table directory,row directory,free,data
2.Tablespace Mangement
LocaL: use bit map
Dictionary: rescusive sql, result in update,insert sql to dictionary
3. create tablespace myts1
datafile '/u01/oradata/lsh/myts1.dbf' size 100m
extent management local uniform size 10k;
create tablespace myts2
datafile '/u01/oradata/lsh/myts2.dbf' size 100m
extent management local autoallocate;
create tablespace myts3
datafile '/u01/oradata/lsh/myts3.dbf' size 100m
extent management dictionary
default storage(
initial 10k
next 10k
pctincrease 10%
maxextent 100m
)
alter tablespace myts3 minimum extent 10k;
alter tablespace myts3
default storage(
initial 10k
next 10k
);
drop tablespace myts1 including contents and datafiles;
resize tablespace
alter database datafile '/u01/oradata/lsh/myts1.dbf' autoextend on next 10m maxsize 100m;
alter database datafile '/u01/oradata/lsh/myts1.dbf' resize 100m;
alter tablespace myts1 add datafile '/u01/oradata/lsh/myts1_1.dbf' size 100m;
rename datafile
alter tablespace myts1 offline;
!cp dest one to one dest
alter tablespace myts1 rename datafile '/u01/oradata/lsh/myts1.dbf' to '/u01/oradata/lsh/myts2.dbf ';
shutdown immediate
!cp one dest to one dest
start mount;
alter database rename file '' to '';
4 status of tablespace
online/offline control access data
read only drop objects
5.System , undo ,temporary tablespace
System tablespace: created by create database or dbca
store data dictionary and system rollback segments
can not be offline
can not be delete
in oracle 9i,using dbca create database ,system tablespace is local,other tablespace must be local.
if system is local ,defualt temporary tablespace must define.
undo tablespace: store undo segment.
local management
current use undo tablespace can not be delete
current use undo tablesapce can not be offline
create undo tablespace myundo datafile '/u01/oradata/lsh/myundo.dbf' size 100m;
temporary tablespace: store temporary segment
default temporary tablespace can not be delete ,offline
create temporary tablespace mytemp tempfile '/u01/ordata/lsh/mytemp.dbf' size 100m;
alter database default temporary tablespace mytemp;