Database Administrator

MySQL modifies the copied user and password In the production environment, you sometimes need to modify the password for copying a MySQL user account, for example, if the password is lost, or because multiple different copy users want to be a single

MySQL sets the default database Encoding If the encoding method is not selected during MySQL installation, the system selects latin1 encoding by default, in the MySQL Console window, enter show variables like 'Char % 'to view the default sequence

Error ORA-02287 Using Sequence Today, a developer asked me a question, saying that the ORA error was reported when an SQL statement was executed. After my mind deleted the permissions, the error he gave me was unexpected.ERROR at line 1:ORA-02287:

Use flashback database to implement flexible data rollback I wrote an article about using the flashback database feature to avoid repeated import of large amounts of data in the test environment, resulting in a waste of time and storage space.The

Oracle RMAN database backup and recovery in non-archive Mode 1. Database Backup in non-archive Mode SQL> archive log list;Database Log mode non-archive ModeDisable automatic archivingArchiving end point USE_DB_RECOVERY_FILE_DESTOldest online log

MySQL error: Unknown character set: 'utf8mb4' Com. mysql. jdbc. exceptions. jdbc4.MySQLSyntaxErrorException: Unknown character set: 'utf8mb4'At sun. reflect. NativeConstructorAccessorImpl. newInstance0 (Native Method)At sun. reflect. nativeconstruct%

Configure MySQL master-slave replication in Linux MySQL master-slave replication is a practical experience that you have always wanted to learn, because the master-slave replication in Oracle also requires a lot of configuration options. In contrast,

Knowledge about Oracle official documents Although many Oracle DBAs have been familiar with Oracle for a long time, they are used to Baidu or Google if they cannot remember the syntax or find corresponding parameters. Although the official

Mysql Study Notes sixteen (database maintenance), mysql Study Notes Data backup data loss cause: storage media applaud, user operation error (accidental deletion of the entire database), server paralysis 1. File Replication needs to stop the server

SQL statement 2Menu column dataSelect name from totoro;Select two columns of dataSelect id, name from totoro;Non-repeated data in the menu ColumnSelect distinct name from totoro;Select the data whose name is pangpang3 in the name column.Select *

Mysql error: Unknown character set: 'utf8mb4', mysqlutf8mb4Com. mysql. jdbc. exceptions. jdbc4.MySQLSyntaxErrorException: Unknown character set: 'utf8mb4'At sun. reflect. NativeConstructorAccessorImpl. newInstance0 (Native Method)At sun. reflect.

[Data Center reconstruction]-trigger operations for divorce firms and trigger Firms I recently learned about the trigger, but now I prefer the trigger as a special Stored Procedure (trigger: you can perform a series of operations on another table

Aerospike-Architecture Distributed, aerospikeDistribution) The Aerospike database is a component provided for 24/7 running applications that can reliably process big data. When developing an application, you don't have to worry about where the

Java. SQL. BatchUpdateException: ORA-12899, ora-12899 Recently, when I used the JDOM component to parse XML file data and store the data to the oracle database, the following error occurs: Exception in thread "main" java.sql.BatchUpdateException:

Customized tablespace retention policies and customized retention policies In large databases, the recycle bin is large, and there is a lot of garbage. It is very slow to query tablespaces. To prevent accidental operations, it is impossible to add

Mysql imports data to excel, mysqlexcel Create a test data table first Create table users ( Username varchar (40) not null, Password varchar (40) not null) charset = utf8; Insert data Insertinto users values ("admin", "admin "); Insertinto users

PostgreSQL tutorial (12): Role and permission management, postgresql permission management PostgreSQL manages database access permissions through roles. we can regard a role as a database user or a group of database users. Roles can have database

PostgreSQL tutorial (11): server configuration, 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

The hbase shell script is written on the SecureCRT terminal and cannot be used to delete keys. securecrthbase I. Description Remote connection to Linux on SecureCRT terminal, and use hbase shell script for Distributed Database Operations, but

Use rocksdb, rocksdb Recently, the project needs to use a key-value data storage. Among the many k-v databases, rocksdb is selected for only one reason. This product claims to support range query. OK. Download git and compile it. here we will talk