Oracle

A database transaction is a unit operation that either succeeds or fails all of the operations. In Oracle, a transaction starts with the execution of the first Data Manipulation language (DML) statement until a commit statement is executed, commits

There was a script that ran for a long time without results, and the results were instantly optimized. The original statement is as follows:sql> explain plan for 2 select * 3 from Crm_dg.tb_ba_channelstaff A, 4 crm_dg.tb_ba_s Ubscription_hist B, 5

--tanslate (STR,FROM_STR,TO_STR)--Replace the from_str in str with the TO_STRSelectTranslate'Hello','e','o') T fromdual;--InStr (STR,DES_STR)--can implement like functionSelectInStr'Hello','g'), InStr ('Hello','h'), InStr ('Hello','L')

NvlThe format of the NVL function is as follows: NVL (EXPR1,EXPR2)The meaning is: if the first parameter of Oracle is empty then the value of the second parameter is displayed, and if the value of the first parameter is not NULL, the first parameter

1. Create a directory directory (role System/sys)Create directory hello_file as ' D:\dupmfile ';--View all the created directory--select * from Dba_directories;--drop directory is used to delete paths.--drop directory Exp_dir;2. Create a tablespace (

The most common example of a segmented query is the lag and lead statistics functions, which allow the lag and lead functions to fetch the first n rows of the same field and the values of the last n rows in a single query. This can be done using

Introduction to Cursors for OracleOracle中的PL/SQL的游标是指把数据库中查询出来的数据以临时表的形式存放在内存中，游标可以对存储在内存中的数据进行操作，返回一条或者一组数据，或者一条数据也不返回。PL/SQL中的记录和表类型虽然也能用来存储数据，但对一组存储在内存中的数据进行操作，还是不太方便，游标恰好是这方面的工具。PL/SQL包含隐含游标和显示游标，其中隐含游标用于处理SELECT

1. Copy the table structure and its data: CREATE TABLE Table_name_new as SELECT * from Table_name_old 2. Duplicate table structure only: CREATE TABLE table_name_new as SELECT * from Table_name_old where 1=2; Or: Create TABLE table_name_new like

When creating an index, we often want to estimate the size of the index to assess the impact on the existing project environment, and we also want the process of creating an index to minimize the impact of the project environment we are executing

Oracle Redo, oracleredo Redo logIn Oracle databases, there is a log file called redo log file, which is commonly known as redolog. There are two types of redolog: Online redo logs and archived logs.ONLINE Redo log Online redo log is mainly used

How Oracle 10G select works, oracleselect Internal execution of database query statements Select * from table Procedure Analysis phase (parse) 1. Does the Shared Pool cache have this statement. If any, directly return results. 2. Check whether

Differences between Oracle Data Pump export and traditional export It is estimated that many of my friends are not clear about the differences between Oracle Data Pump export and traditional export. The following small series will introduce you to

[ORACLE] analyzes 23 oracle sessions and performance statements -- View Cluster wait cache busy -- wait for resource buffer busy -- data block consistent read wait SELECT inst_id, event, p1 file_number, p2 block_number, wait_timeFROM gv $

Oracle Import/Export (used more)1. create directory (role system/sys) create directoryHello_fileAs'D: \ dupmfile';-- View all created Directories-- Select * from dba_directories;-- Drop directory. -- Drop directory exp_dir;2. create a tablespace

Basic oracle database operation statementsThis article mainly introduces the basic statements and concepts of oracle database management. 1. How to query the permissions of a role? A. select * from dba_sys_privs where grantee = 'connection' or

Oracle memory problems In Oracle, the memory structure mainly includes two categories: SGA and PGA. SGA represents the system global zone, and PGA represents the program global zone. Oracle memory mainly stores the execution program code (PL/SQL,

Some problems encountered during RH + Oracle installation are worth summarizing Yesterday, when I installed a RH5 + Oracle version in the middle of the night, I encountered several things and stated the following. 1. you need to configure the kernel

How can I use partitions for hierarchical queries of Oracle partition tables? Recently, When I optimized the hierarchical query of a partition table, I found that partitions were not used. I did an experiment and found that partitions could still be

[Oracle] view INVALID of the CBO version Source: Oracle 11.1.0.7 Target end: Oracle 11.2.0.4 In the CASE of a recent data migration, the status of a VIEW changes from VALID to INVALID after the data migration is completed. The VIEW creation

Method R) R indicates the response time ). The specific definition is as follows: 1. Target the tasks that are critical to the business. 2. Collect properly scoped, un-aggregated profile data for each task while the task is exhibiting the behavior