Database Administrator

1.1 error ORA-600 [kcratr_nab_less_than_odr], cannot start 1. symptom Description: The server storage is powered off, causing the database to go down and start the database again. The database cannot be started normally. The database reports the

Oracle 12c has a new feature that can archive data in the database, hide infrequently accessed data from the application, and set it to inactive. Of course, it can also be displayed at the session level. This is achieved through the row archival

Syntax: Test_expression BETWEEN begin_expression AND end_expressionFor example: The database AA table has an AA_RQ field, which is declared, Oracle AA_RQ VARCHAR2 (8 ),SQL Server AA_RQ VARCHAR (8 ),The following two statements have

The previous articles are based on what you see and know, and are integrated with the predecessors to gain a preliminary understanding of the concept of big data. In the next four articles, we put aside the concept and basic knowledge of big data

Today, my colleague said that a machine had a power outage during the holidays. After the machine was restarted, I logged on to the server using PLSQL: A ORA-01034: ORACLE not availableORA-27101: shared memory realm does not existLinux_x86_64 Error:

Background: The monitoring script SHELL finds it troublesome to log on to the server every day, and the number of servers is growing. Originally, I wanted to use the SendMail function of the system, but the company said it was not safe. You have to

Use MySQL Migration Toolkit to quickly import Oracle Data to MySQLLet's talk nonsense first.I have recently learned some database knowledge. I have been familiar with Oracle and MySQL before, and recently I am very popular with MongoDB

MySQL replication is asynchronous, that is, non-synchronous. It does not verify data consistency in the database, as long as the SQL syntax is correct and there is no error, it can be successfully executed. MASTER@root@test 12:20:40>create table

Anyone familiar with MySQL may know that MySQL has an "insert ignore" syntax to ignore existing records. PostgreSQL does not currently provide such syntax, but it can be replaced by other methods.The following shows the sample table structure and

/* Function called at startup to load RDB or AOF file in memory. */void loadDataFromDisk(void) { long long start = ustime(); if (server.aof_state == REDIS_AOF_ON) { if (loadAppendOnlyFile(server.aof_filename) == REDIS_OK)

Both PostgreSQL and Oracle provide statements such as row_number () over () to rank corresponding fields, which is very convenient. MySQL does not provide such a syntax.Recently, due to the increasing demand for migrating data from Oracle to MySQL,

Http://www.infoq.com/cn/news/2014/01/couchdb-creator-joins-salesforce Recently, the founder of NoSQL database CouchDB announced that it would join Salesforce.com to engage in a very "cool" project related to the vendor's cloud

A database is a collection of large amounts of data that can be shared and organized in a computer that has been stored for a long time.1. database data features P4Permanent storage, organized, and shared.2. Data independence and how to ensure P10

Show status like 'value'; query the performance of the MySQL database. Value Parameter Connections: Number of times the MySQL server is connected Uptime: MySQL Server launch time Slow_queries: Number of slow queries Com_lelect:

There was a mysql event that failed to be executed since last night:Event execution failed. No specific error message is displayed. An error is returned after the code for manual execution time is run:Failed to read auto-increment value from

Can the internal data be recovered when the hard disk breaks down? Recently, it was really a headache because the hard drive broke down. Fortunately, I met a great god and helped me solve the problem. I am very grateful to him for introducing this

1. Open the database:Note: To open a database, the file name does not have to exist. If the file does not exist, sqlite will be automatically created. The first parameter refers to the file name, and the second parameter is the defined sqlite3 **

The current status is dg1 as the master database, and the slave database is dg2.First check the status of the Master/Slave database:Dg1 SQL> select name,database_role,OPEN_MODE,SWITCHOVER_STATUS from v$database;DATABASE_ROLE OPEN_MODE SWITCHOVER_

We often traverse the system tables in the data dictionary to write SHELL scripts or dynamically create data. Here I use PLSQL to demonstrate three methods to traverse a table. The table structure is as follows, t_girl=# \d tmp_1;

PostgreSQL does not have binary logs similar to MySQL, but there are REDO logs similar to MySQL, and there is a REDO archiving function not available in MySQL. Of course, REDO archiving has been implemented by MariaDB and Percona-MySQL. Then we can