Database Administrator

In the previous article, we tested and tested the existing redis data structure (see ). We will test some common redis commands today: You need to check the data volume of the current database. There are three methods: keys *, dbsize, and info

1,Control File(Controlfile)Loss recovery Based on the control file's compound multi-path nature, there are two types of loss: one is the damage or loss of a control file, and the other is the loss of all control files. In the first case, you only

First, let's introduce the history. In Oracle 9i/10g, if one database instance needs to be evicted (an ora-29740 error occurs in the evict, alert file) for another instance, you need to write the relevant information in the control file (CF) through

Install three nodes on a set of Oracle 11gr2, but the dm paths of the multipath disks found by the three nodes are inconsistent, and the corresponding dm paths change after the restart: [Root @ db3 ~] # Multipath-l | grep dmMpath2 (3600140000125d8a52

If the current system time of Oracle is inserted, SYSDATE can be used. Insert into floor values (SYSDATE );Insert Date data to Oracle Database (to_date usage) Today, I encountered the need to insert date data into the Oracle database. I want to

HBase tables have the following features: 1 large: A table can have hundreds of millions of rows and millions of Columns 2. Column-oriented: storage and permission Control for columns (families), and independent column (family) retrieval. 3 sparse:

In my application, I need to generate a random password for this account when the user registers for the first time. The generated password must meet certain requirements. These requirements must be configured by the system administrator. We provide

In Mysql databases, Merge tables are somewhat similar to views. Mysql's merge engine type allows you to merge many tables with the same structure into one table. Then, you can execute the query. The results returned from multiple tables are the same

Common Oracle DBA operations Modify language environment Change Chinese environment to English environment Alter session set als_language = 'American '; Change the English environment to a Chinese Environment Alter session set nls_language =

1. To access the Db2 database, first load the following lib:Db2jcc. jar, db2jcc_license_cu.jarYou can find them in C: \ Program Files \ IBM \ SQLLIB \ java.2. If the user does not have the permission to access the table, open the Db2 control center,

The operating system where the database is located has crashed and the database system has been restored. 1) ensure that all files (installation files, data files, and log files) in the database are in one partition, and all logs and files related

Environment: OS: Red Hat Linux As 5DB: 11.2.0.1 11G has greatly improved the volume uard, the slave database can still apply the archive logs uploaded from the master database. Remember to open the slave database to check whether the data has been

After sybase 12.5.4 is installed on RedHat as 4 and Initialization is complete, run isql-Usa-P to report the error: The context allocation routine failed when it tried to load localization files !!One or more following problems may caused the

When you delete a record in the mysql database today, the following error message is displayed: Error Code: 1175. You are using safe update mode and you tried to update a table without a WHERE that Uses a KEY column To disable safe mode, toggle

I did not know much about the remote restoration of the RMAN backup database. When I went to Shangguan technology to attend lectures last Saturday, teacher Zhang lie is talking about RMAN backup, so he has recovered a lot of memories and understood

The development process has been running on the local mysql Data. After the test is completed, connect to the LINUX Server database. The result is always an error and the table cannot be found! What I wonder about is that the table is clearly

1. Overview New Features of Oracle 10g InMemory Undo: From the previous introduction, we can know that the Undo management method is the same as the conventional data management method. when data is modified, a pre-created image is created in the

If you want to perform one-way MySQL Data Synchronization, read another article: I. Prepare the environmentMaster:Ip: 192.168.211.128Mysql version: 5.0.77 (you can view it by running the command mysqladmin-uroot-p123 version)Slave:Ip: 192.168.211.131

SQL> alter database add logfile thread 1 group5 ('+ data/myrac/onlinelog/myrac1_redolog_group5_01') size 100 m; SQL> alter database add logfile member '+ data/myrac/onlinelog/myrackets redolog_group5_02' to group 5; SQL> alter database add logfile

The DECODE function is one of the powerful functions of Oracle PL/SQL. Currently, only oracle SQL provides this function, and other database vendors do not yet implement this function. What is the purpose of DECODE? First, let's construct an example.