Database Administrator

1. Are you familiar with databases SQL2005 and Oracle? SQL2005 is a database product of Microsoft. It is an RDBMS database, which is generally used in some medium-sized databases and cannot be used across platforms. ORACLE is a data product of

A friend configures the DG of the master database and the physical slave database. After the configuration is complete, he finds that there is a slave database which cannot receive the archive logs of the master database. Logs cannot be transmitted

Recently, the company needs to build Oracle9i on a 64-bit RedHat system, which is a relatively old version and is difficult to install. The general installation process is as follows: 1. Download the installation package 1、amd64_db_9204_disk1_1-32.16

1. Classification of constraints. Constraints are divided into five categories: 1. not null, 2. primary key, 3. check, 4. unique, 5. foreign key. 1.1 not null Constraint By default, the values of all columns can contain null values. When the not

This is a production database's rman backup shell script, divided into zero-level backup and one-level differential cumulative backup, zero-level backup once a week, and other one-level differential cumulative backup. 1. Zero-level backup shell

Recently, an error occurred in the Oracle database data file of a customer, resulting in a failure to start.After recovery, the data file status is normal and the database seems to be open.(Note that the database status is normal. This does not mean

Use the Oracle database cluster management tool on the rac1 node to stop the rac1 instance and use the crs cluster tool to stop the CRS cluster service: Stop Note: Stop the instance before stopping the CRS service. Start Note: Start CRS first. to

The developer asked me to set an Oracle 11g sga slightly larger. Therefore, follow the previous 10 Gb memory operation on oracle.[Oracle @ localhost db_1] $ sqlplus/nolog SQL * Plus: Release 11.2.0.1.0 Production on Saturday June 30 13:42:07

In the Oracle data guard environment, the alert. the error message "ORA-12514: TNS: listener does not currently know of service requested in connect descriptor" appears in the log file, causing the logs on the master database to fail to be

Slave processes is the background process that represents the execution of other processes.  I/O Slave Processes I/O slave processes (Innn) simulate asynchronous I/O for systems and devices that do not support it. in asynchronous I/O, there is no

Record PCM lock information in GRD It is located in the SGA of each instance However, each instance only contains part of GRD, And the GRD of all instances is a complete GRD. PCM lock has three main attributes: Mode, Role, and PI. ① Mode -- S -- X --

MySQL multi-Table update can be written in several different ways. Assume that we have two tables. One Table stores Product information for the Product table, with the Product Price column Price. The other table is the ProductPrice table, update the

During the Oracle storage test, it is found that the values of many columns in the product table may be null, resulting in not exists results inconsistent withThe test is as follows:-- Construct two tables with the same table structureSQL> desc

The select statement in Oracle can use the start with... connect by prior clause to implement recursive queries. The connect by clause is used in structured queries. Its basic syntax is as follows: Select... from Where Start with Connect by ; :

On the Red Hat Enterprise Linux platform, the MySQL master-slave synchronization principle is used to achieve two-way MySQL synchronization.MySQL version: 5.5.28Operating System: RHEL 5.8 32bitServer1: 192.168.1.1Configuration: my. cnf Server-id =

1. view the current DB2 copy on the system: [Root @ localhost home] # db2ls   Install Path Level Fix Pack Special Install Number Install Date Installer UID Bytes ----------------------------------------------------------------------------------------

On MySQL, the index Merge function is added, and two indexes can be used for one SQL statement. The following is an example: Mysql> select * from t; + ------ + | A | B | + ------ + | 1 | 24 | | 4 | 1 | | 1 | 20 | | 4 | 26 | | 5 | 10 | | 4

The current environment is a dual-node RAC with the version of Oracle 10.2.0.5. The hostname is racnode1, and racnode2 needs to add a new node racnode3. The OS version is Oracle Linux 5.7 x86_64 Ensure normal operation of RAC Configure public IP,

You do not need to limit the expiration time of your account during development, so you need to make some settings. 1. Check the user's proifle, which is generally default: SELECT username, profile from dba_users; 2. view the password validity

I. Overview Prior to Oracle9i, DBA is responsible for collecting object statistics. By default, the database does not provide object statistics. At oracle10g, a job is created and scheduled to periodically collect object statistics when you create a