Database Administrator

DUAL table:Dual enables the system table, whose owner is the sys user. Cannot be deleted.All users can access it.A dual table is also called a virtual table.There is only one field in the dual table. This field makes dummy. SQL> DESC DUAL;Is the

We know that Oracle will switch logs when the current online logs are full or some conditions are met, or when logs are manually switched, even if the current online log group is from this log group to another log group, the log loop mechanism is

In general, CentOS has installed the libevent binary library by default, but no header file for development is installed.Therefore, you can use the following command to install: Yum install libevent-devel Next, you can download the latest memcached

1. Write the URL for connecting an application to Oracle racJdbc: oracle: thin: @ (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP) (HOST = 192.168.30.52) (PORT = 1521) (ADDRESS = (PROTOCOL = TCP) (HOST = 192.168.30.51) (PORT = 1521) (LOAD_BALANCE = yes)

Flashback is not completely restored. drop table: The table name of the deleted table does not seem to have been changed, and it is not actually dropped (the recycle bin of windows) --> flash dropped table TechnologySQL> show recyclebinORIGINAL NAME

The tnsping service name of the XP Oracle client is normal, but cannot be entered with SQLPLUS. The error message is: ORA-12514: TNS: The Listener currently cannot identify the request service in the connection Descriptor Check that the tnsnames.

One way to access MySQL using Python in Linux is to use the MySQLdb module. The following describes how to install MySQLdb in Linux. (1) download MySQLdb Download the latest MySQLdb, http://sourceforge.net/projects/mysql-python/ from SourceForge.net,

When catalog is not used, all configuration information in rman is recorded in the control file. Dump information in the control file: **************************************** ***********************************RMAN CONFIGURATION RECORDS*************

Some things can only be exposed during long stress tests. The MongoDB cluster has been in use for several months, but after a long-running stress testing program is written, the primary server cannot be started for a few days. View MongoDB log error

1. Review In the previous article, we talked about the use of percona-xtrabackup software. This article describes how percona-xtrabackup achieves Incremental backup and recovery.2. Incremental Backup  How to Implement Incremental backup and recovery

For "ORA-01722: Invalid Number error" always encountered before, today again encountered! Cause: It is common to convert fields to the number type. For example, it is common to create a materialized view if a column needs to be converted to a

1. Download MySQL 5.6Download Page: http://dev.mysql.com/downloads/mysql/this option is selected using Red Hat Enterprise Linux 6/Oracle Linux 6 (x86, 32-bit), RPM Bundle. Download to/root/Downloads "2. decompress the tar package

08:29:43 WARNING OGG-00869 Oracle GoldenGate Delivery for Oracle, rep_app.prm: No unique key is defined for table 'C '. all viable columns will be used to represent the key, but may not guarantee uniqueness. KEYCOLS may be used to define the key.08:2

Language _ region. Character SetSIMPLIFIED CHINESE_CHINA.ZHS16GBK Set nls_lang = 'simplified CHINESE_CHINA.ZHS16GBK'   Oracle modifies the server character set:SQL> SHUTDOWN IMMEDIATE; SQL> STARTUP MOUNT; SQL> ALTER SYSTEM ENABLE RESTRICTED SESSION;

Oracle uses ASM for storage. By default, there is only one control file for database creation. To add more control files, you must manually add them. The following are the specific steps: 1. view the current control file [Oracle @ Oracle-LAB dbs] $

1. Bolb field description: Writing Blob fields is very different from writing other types of fields. Because Blob itself has a cursor, you must use cursor to operate blob. Therefore, before writing Blob, you must obtain the cursor to write data. How

In Windows, Oracle 11g cannot be started normally after a shutdown and cannot be started to the mount state: ORA-03113: end-of-file on communication channel Process ID: 4276 Session ID: 1286 Serial number: 2 Find the trc file of the corresponding

Use yum install mysql-mmm for installation. After the mmm software is installed, the configuration is completed, but the following error is reported when the/usr/sbin/mmm_control show command is executed: ERROR: Can not connect to monitor daemon!

Oracle RAC client failover (failover). When using the TAF method, the client that has established a connection does not need to send a connection request again when the connected instance or node fails, the previous database operations can still be

In the morning, you receive an alert email from a Linux server disk and an email from the monitoring Alert Log program. After the check, it is found that there is no space for a partition in the Linux server. The main reason is that the programmer