Database Administrator

Installing MySQL in Ubuntu saves a lot of trouble. Basically, I sorted out the online materials.1. Install MySQL Sudo apt-get install mysql-server mysql-client # You will be asked to enter the root user password once in the middle   Sudo

Mysql master-master replication architecture configuration The master-slave replication structure of MySQL is different from the master-slave replication structure. In the master-master replication structure, any changes to the data inventory on one

Subquery: When a query result is a condition of another query, it is called a subquery. Notes for using subqueries: Subqueries can be nested in multiple layers The subquery must be enclosed in parentheses (). Subquery Syntax: SELECTSelect_list

Cocould not load program Oracledevmdm:Symbol resolution failed for/usr/lib/libc. a [aio_64.o] because:Symbol kaio_rdwr64 (number 1) is not exported from dependentModule/unix.Symbol listio64 (number 2) is not exported from dependentModule/unix.Symbol

Ubuntu 11.10 environment. [Most commands require the root permission. You can use the root operation or add sudo to the command] For more information about Oracle, see Oracle topics page http://www.bkjia.com/topicnews.aspx? Tid = 12 1. Download

You can use the FORALL statement to Perform Batch INSERT, UPDATE, and DELETE operations in Oracle. Syntax: -- Syntax 1: FORALL subscript variable (can only be referenced as subscript)INLower limit... Upper Limit SQL statement;-- Only one SQL

Oracle set operation combines two or more result sets into one result set. Result set operations include: INTERSECT (intersection) returns the records that are common to the two queries. Select deptno from dept intersect select deptno from emp;

You should alwayshibernate.dialectSet Properties to correctorg.hibernate.dialect.DialectSubclass. If you specify a dialect, Hibernate uses reasonable default values for some of the attributes listed above, so you do not need to manually specify them.

Determines whether to use spfile or pfile when Oracle is started. The default initialization file used after Oracle 9i is spfile. We can use the following three methods to determine whether it is SPFILE or PFILE to start the database.1. show

Delete diskgroup on an Oracle 11g ASM instance. An error occurred while deleting the ORA-15027: active use of diskgroup precludes its dismount, as shown below: SQL> drop diskgroup webdg including contents; Drop diskgroup webdg including

When creating a 10g Database on the ASM instance of Oracle11.2 RAC, an error is reported: The Cluster Manager cannot be connected, and the ASM instance cannot be located. The error message is as follows:ORA-15077: cocould not locate ASM instance

1: List the names, department names, and salaries of all employees. Select a1.ename, a1.sal, a2.dname from emp a1, dept a2 where a1.deptno = a2.deptno; 2: List detailed information about all departments and number of departments Select a2.deptno, a2.

Backup OverviewLogical backup:There are two types of backup: , Physical backup and logical backup Physical backup: This method completely restores the database, but requires a large number of external storage devices, such as tape libraries,

Quick View of the database connected by the Oracle service name: The specific operation command and result information are as follows: ------------------------------------------------------------------ C: \ Documents ents and Settings \

1. Start and close server processes:The following are the usage and common options of the pg_ctl command. It should be noted that this command is the encapsulation body of the S command, so it is more convenient to use than using postgres

I. Oracle cluster architecture Oracle RAC is the Real Application Cluster of Oracle. It is a parallel Cluster system provided by oracle. The entire Cluster system is composed of Oracle Clusterware (Cluster ready software) and Real Application

Oracle null test question Create table TABLE1 ( ID VARCHAR2 (10) not null, Grzhye number (10, 2 ), GMSFHM VARCHAR2 (18 ), RYLB varchar2 (10 ), CARDNO VARCHAR2 (20 )); Comment on column TABLE1.ID is 'personal number '; Comment on column TABLE1.GRZHYE

Migrate a user from an Oracle database to another database. The migrated data volume is about 120 GB. If you use expdp to export data, it will take a long time. In addition, the exported DMP file copy and impdp import time cannot meet the

In Oracle databases, the tools used to execute scheduled tasks are generally DBMS_JOB packages. This package is easy to use and has a long history and is still widely used. Frankly speaking, this package's functionality satisfies the scheduling task

Preparation:Server Port Data Directory log replica set key fileServer1 28010/app/mongo/mongodb/data/sets/r0/app/mongo/mongodb/data/sets/log/r0.log/app/mongo/mongodb/data/sets/key /r0Server2 28011/app/mongo/mongodb/data/sets/r1/app/mongo/mongodb/data/