虚拟机ORACLE10G Data Guard(DG) Physical Standby Database
今天小测了一下10g的physical DG，参考首选官方文档
dgsource :192.168.1.100
dgtarget:192.168.1.245
ORACLE 9i-23ai
数据库oracle
oracle password file(口令文件) 文件名格式重要性
今天测试dg，用sys +tnsnames 中指定别名文件远程服务怎么也连不上，ORA-01031: insufficient privileges
查看oracle10g官方文档没发现这个格式问题（可能是我大意了）,orapwd file的格式是有限制的，
oracle 禁用表的DDL 实现真正的READ ONLY
1，只读表空间可不可以后来创建表
2，只读表空间里先创建的表能不能删除
3，read only 是不是只禁用dml?
…
ORACLE远程DMP备份策略
ORACLE加WIN计划任务实现ORACLE数据的定时压缩包形式备份。
ORACLE透明网关使用-实践后可用
网络上很多份关于透明网关的资料。但是真正通过实践能够配置成功，目前只发现了这一份。
实践出真知！
oracle11g Expdp COMPRESSION(数据泵压缩增强)
今天看oracle11g新特性发现宣称11G,用了新的zlib算法在压缩上改变很多,可以比oracle10g压缩算法快40%，空间减少20%，准不准不先不说，测试看应用有什么变化吧…
oracle11g add default values columns(增加默认值列的改进)
oracle 11G 对 现有表增加指定默认值列方式发生了很大变化，无论是存储方式上,还是效率上，下面看一个简单的实验
oracle11g掩盖敏感数据(remap_data)
不知道你有没有遇到过开发的需求导一份生产库的数据到测试库，但库表中有敏感信息如手机、身份证号等等等等，如果你全部把真实的数据给他们是不是太不负责人了(当然很多都这么做了),少导列可能会影响测试准确性,最好是用其它掩码覆盖…
BLOB select、insert、exp with sqlplus
SQL> create table testblob(id int,comm blob);
Table created.
ORA-06502: PL/SQL: numeric or value error: character string buffer too small
ERROR at line 1:
ORA-06502: PL/SQL: numeric or value error: character string buffer too small
ORA-06512: at “WMSYS.WM_CONCAT_IMPL”, line 30
DML error capture (捕获DML错误日志)
今天发现用dbms_errlog可以捕获错误日志，很给力，直接看实验
[oracle@orazhang ~]$ sqlplus anbob/anbob
fast delete, Best practice on Very large table
Today I read foreign blog,I think I learned the true knowledge
One of most operations we are performing is “Deleting many rows from oracle big tables” ;
利用rowid快速在线更新海量数据
declare
maxrows number default 1000;
row_id_table dbms_sql.Urowid_Table;
currcount_table dbms_sql.number_Table;
cursor cur_t2 is….
trigger一点儿小发现new or :new、ORA-04091
If you delete the line “FOR EACH ROW” from the trigger, it becomes a statement trigger which is not subject to this restriction, and the trigger.
Backups to tape can only be backup sets. use rman
By default, RMAN creates all backups as backup sets, on tape or on disk. You can change the default backup type for disk backups to be image copies using the CONFIGURE command. Backups to tape can only be backup sets.
oracle同一实例不同用户之间所有对象的数据导入
同一实例下，不同用户之间的数据同步导入
1，exp from a user,imp to b user,
2,impdp network_link,不生成dump文件直接导入
…
HWM 高水位储存位置
Extent Header:: spare1: 0 spare2: 0 #extents: 4 #blocks: 32
last map 0x00000000 #maps: 0 offset: 2716
Highwater:: 0x02400391 ext#: 3 blk#: 8 ext size: 8
Loss database default tablespace files affected and recovery
接上一篇，
如果丢失数据库默认表空间的任一数据文件，数据库会不会shutdown?
Any loss of controlfile effects of database and recovery the controlfile
Your database is having two control files, three redo log file groups with two members in each group. Failure of which file would cause an instance to shut down
loss of all controlfile,database is automatic shutdown abort?(丢失所有控制文件，数据库会关闭？)
Your database is configured in NOARCHIVELOG mode. All the control files have been lost due to a hard disk failure but the data files are not lost. You have the closed whole database backup available to you…