oracle创建多个数据库

‘壹’ oracle 一个实例下可以建多个数据库么

一
通常情况下：一个实例对应一个数据库
二
RAC集群：多个实例对应一个数据库
三
oracle12C:一个实例可以对应多个数据库

‘贰’ oracle可以创建多个数据库吗

不管你是什么操作系统，可以按照下列的方式创建多个Oracle数据库点击[开始]->[程序]->[Oracle - OraHome92]->[Configuration and Migration Tools]->[Database Configuration Assistant]，然后按照中文提示创建自己的数据库!!
Oracle和sql不一样，可以说是复杂的多，用惯了SQL的朋友真的是很难接受Oracle的操作方式,

‘叁’ oracle 一个实例下可以建多个数据库么

oracle 一个实例下可以建多个数据库么？
:一 通常情况下:一个实例对应一个数据库 二 RAC集群:多个实例对应一个数据库 三oracle12C:一个实例可以对应多个数据库

‘肆’ 怎样再oracle中建立多个数据库

通过oracle自带的DBCA建数据库。

‘伍’ oracle创建三个数据库和创建一个数据库后创建三个表空间的区别

有很大的区别，放一个数据库是最合理的，放多个数据库中，这些数据如果需要互访，会很麻烦，也有有主机资源、存储
资源浪费
、网络资源、人力管理资源

‘陆’ oracle中如何建立多个数据文件

一个是建立表空间时创建多个
数据文件
CREATE
TABLESPACE
tablespace_name
DATAFILE
data1...
data2...
另外就是新增数据文件到现有的表空间下
ALTER
TABLESPACE
tablespace_name
ADD
DATAFILE
data3...

‘柒’ Oracle新建数据库

Oracle新建数据库可以参考以下操作方法：

1、首先点击桌面左下角的开始图标；

‘捌’ oracle10G怎么里怎么创建多个数据库

一个数据库创建多个实例
1. 先要关闭数据库（进程和内存关闭）
[Oracle@oracle_2 ~]$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.1.0 - Proction on TueNov 12 20:34:53 2013
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release10.2.0.1.0 - Proction
With the Partitioning, OLAP and Data Mining options
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> exit
2. 设置环境变量
[oracle@oracle_2 ~]$ vi .bash_profile
此时环境变量已经设置好了
3. 创建目录
i. 创建相关文件
此时我们可以看见已经有了相关目录，那是我们之前创建的实例ORCL的相关目录
创建目录是采用了批量创建目录{a,b,c,u}mp
[oracle@oracle_2 ~]$ cd $ORACLE_BASE
[oracle@oracle_2 oracle]$ ls
admin flash_recovery_area oradata oraInventory proct
[oracle@oracle_2 oracle]$
[oracle@oracle_2 oracle]$ mkdir -p admin/ORA10G/{a,b,c,u}mp
[oracle@oracle_2 oracle]$ ls
admin flash_recovery_area oradata oraInventory proct
[oracle@oracle_2 oracle]$ cd admin/
[oracle@oracle_2 admin]$ ls
ORA10G ORCL
[oracle@oracle_2 admin]$ cd ORA10G/
[oracle@oracle_2 ORA10G]$ ls
amp bmp cmp ump
[oracle@oracle_2 ORA10G]$
[oracle@oracle_2 ORA10G]$ ls
amp bmp cmp ump
[oracle@oracle_2 ORA10G]$ cd ..
[oracle@oracle_2 admin]$ ls
ORA10G ORCL
[oracle@oracle_2 admin]$ cd ..
[oracle@oracle_2 oracle]$ ls
admin flash_recovery_area oradata oraInventory proct
[oracle@oracle_2 oracle]$ mkdir -p oradata/ORA10G
[oracle@oracle_2 oracle]$
ii. 创建密码文件
创建密码文件需要到ORACLE_HOME/dbs目录下创建
[oracle@oracle_2 10.2.0]$ cd $ORACLE_HOME/dbs
[oracle@oracle_2 dbs]$ ls
hc_ORCL.dat initdw.ora init.ora lkORCL orapwORCL spfileORCL.ora
[oracle@oracle_2 dbs]$ orapwd
Usage: orapwd file=<fname>password=<password> entries=<users> force=<y/n>
where
file -name of password file (mand),
password- password for SYS (mand),
entries -maximum number of distinct DBA and force - whether to overwrite existing file (opt),
OPERs (opt),
There areno spaces around the equal-to (=) character.
[oracle@oracle_2 dbs]$ orapwd file=orapwORA10Gpassword=oracle entries=30
[oracle@oracle_2 dbs]$ ls
hc_ORCL.dat init.ora orapwORA10G spfileORCL.ora
initdw.ora lkORCL orapwORCL
[oracle@oracle_2 dbs]$
[oracle@oracle_2 dbs]$ cat init.ora |grep -v^#|grep -v ^$ >initORA10G.ora
[oracle@oracle_2 dbs]$ ls
hc_ORCL.dat init.ora lkORCL orapwORCL
initdw.ora initORA10G.ora orapwORA10G spfileORCL.ora
[oracle@oracle_2 dbs]$
[oracle@oracle_2 dbs]$ vi initORA10G.ora
将内容改的和下面的一样
db_name=ORA10G
db_files = 80 # SMALL
db_file_multiblock_read_count = 8 #SMALL
log_checkpoint_interval = 10000
processes = 50 # SMALL
parallel_max_servers = 5 #SMALL
log_buffer = 32768 # SMALL
max_mp_file_size = 10240 # limit trace file size to 5 Meg each
global_names = false
control_files =(/u01/app/oracle/oradata/ORA10G/ora_control1.ctl,/u01/app/oracle/oradata/ORA10G/ora_control2.ctl)
sga_max_size=300m
sga_target=300m
4. 启动实例为ORA10G的数据库
[oracle@oracle_2 dbs]$ export $ORACLE_SID=ORA10G
[oracle@oracle_2 dbs]$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.1.0 - Proction on TueNov 12 21:08:55 2013
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Connected to an idle instance.
SYS@ORA10G>
SYS@ORA10G>create spfile from pfile;
File created.
SYS@ORA10G>startup nomount;
ORACLE instance started.
Total System Global Area 314572800 bytes
Fixed Size 1219184 bytes
Variable Size 96470416 bytes
Database Buffers 213909504 bytes
Redo Buffers 2973696 bytes
SYS@ORA10G>
SYS@ORA10G>show parameter undo
NAME TYPE VALUE
------------------------------------ -----------------------------------------
undo_management string MANUAL
undo_retention integer 900
undo_tablespace string
SYS@ORA10G>
修改参数，由于undo_management参数为静态参数，所以需要加上scope=spfile
SYS@ORA10G>alter system set undo_management=autoscope=spfile;
System altered.
SYS@ORA10G>show parameter undo
NAME TYPE VALUE
------------------------------------ -----------------------------------------
undo_management string MANUAL
undo_retention integer 900
undo_tablespace string
SYS@ORA10G>shutdown immediate
ORA-01507: database not mounted
ORACLE instance shut down.
此时发现并没有更改，是由于静态参数需要重启才有效
SYS@ORA10G>startup nomount;
ORACLE instance started.
Total System Global Area 314572800 bytes
Fixed Size 1219184 bytes
Variable Size 96470416 bytes
Database Buffers 213909504 bytes
Redo Buffers 2973696 bytes
SYS@ORA10G>
此时只是改了spfile的参数还需要改pfile的参数
SYS@ORA10G>create pfile from spfile;
File created.
SYS@ORA10G>
5. 多个实例的切换
i. 实例为ORCL启动数据库
[oracle@oracle_2 dbs]$ export ORACLE_SID=ORCL
[oracle@oracle_2 dbs]$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.1.0 - Proction on TueNov 12 21:19:19 2013
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Connected to an idle instance.
SYS@ORCL>
ii. 实例为ORCL10G启动数据库
SYS@ORCL>exit
Disconnected
[oracle@oracle_2 dbs]$ export ORACLE_SID=ORA10G
[oracle@oracle_2 dbs]$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.1.0 - Proction on TueNov 12 21:24:54 2013
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release10.2.0.1.0 - Proction
With the Partitioning, OLAP and Data Mining options
SYS@ORA10G>