随笔分类 -  Oracle Performance

摘要：“如果你可以使用一句SQL解决的需求，就使用一句SQL；如果不可以，就考虑PL/SQL是否可以；如果PL/SQL实现不了，就考虑Java存储过程是否可以；如果这些都不可能实现，那么就需要考虑你是否真的需要实现这个需求。”参考网址:http://www.oracle-base.com/articles/misc/string-aggregation-techniques.php#listagg http://www.oracle-base.com/articles/misc/lag-lead-analytic-functions.php http://space.itpub... 阅读全文

摘要：1、将字符串转换为日期:可以不用TO_DATE1 SELECT * FROM EMP E WHERE E.HIREDATE < DATE '2012-08-09'2、从子查询中删除数据1 DELETE FROM (SELECT * FROM DUAL)3、查询所有的系统默认参数1 SELECT * FROM NLS_DATABASE_PARAMETERS;2 SELECT * FROM NLS_SESSION_PARAMETERS;4、查询数据库的信息1 SELECT * FROM v$database;4、查询实例的相关信息:包括主机名，启动时间，当前的状态，版本信息1 阅读全文

摘要：参考网址:http://www.oradev.com/regular_expressions_sql_oracle.jspMetacharactersMeaningExamples\Indicates that the match character is a special character, a literal, or a backreference. (A backreference repeats the previous match.)相当于转义符\n matches the newline character,\\ matches \, \( matches (, \) matc 阅读全文

摘要：As of Oracle Database 10g, you can use the flashback table and flashback databasecommands to simplify your data-recovery efforts. The flashback table commandautomates the process of restoring a full table to its prior state. The flashbackdatabase command flashes back an entire database, and it req.. 阅读全文

摘要：几种常见的Oracle备份方法:The backup methods provided by Oracle can be categorized as follows:■ Logical backups using Data Pump Export and Import■ Logical backups using Export (and its companion utility, Import)■ Physical file system backups: offline backups and online backups■ Incremental physical file syste 阅读全文