SQL Server的链接服务器技术总结
基于WIN平台SQLSERVER数据库的异构数据连接方式总结。
SQLSERVER 连接 MYSQL
SQLSERVER 连接 ORACLE
SQLSERVER 连接 格式化文本文件
SQLSERVER 连接 SQLSERVER(基于OLEDB)
SQLSERVER 连接 ACCESS
SQLSERVER 连接 SYBASE
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
