Database Administrator

Create test tableCreate table test1SELECT *FROM all_objectsWHERE 1 = 2;MATCHED and not matched clauses are optional ① Both clauses appear.Merge into test1USING all_objects BON (a. object_id = B. object_id)WHEN MATCHED THENUpdate set a. status = B.

Differences between sys and system users 1) The most important difference is that the importance of stored data is different. Base tables and views of all Oracle data dictionaries in sys are stored in sys users. These base tables and views are

Rman can be used to back up and restore data files, control files, archive logs, etc. It can also be used as a completely and incomplete Oracle recover tool. It is controlled by the command line or the backup manager GUI of the OEM. RMAN is

1. Operating System commands require OS users: Bash-3.2 $ strings-a $ IEX_TOP/patch/115/import/US/iexmdmsg. ldt | grep '$ Header' # $ Header: iexmdmsg. ldt 120.88.12000000.15 2008/12/08 18:05:52 ehuh ship $ 2. Through SQL, DB users are required:

Audit problem: when the sys user is audited, the audit file that records sys user operations cannot be found in audit_file_dest. I installed an Oracle 10g (10.2.0.3.0) on Windows 7. I did the same thing and found that the audit records of common

Introduction: My friend used rm for a moment. I deleted the Oracle data file and asked for help. When I was helping my friend restore the database, When I encountered a recover, if an error is reported, the archive log no. 28739 cannot be found, so

1 oradebug Introduction Oradebug is mainly used by Oracle Support staff. Although it was very early, it is rarely recorded on the oracle official website. It is an SQL * plus command line tool. You can log on with sysdba permissions without special

The following prompt message is displayed in the mysql Log file, which is related to the federated engine. This option is added during compilation but is not enabled in the configuration file, for more information about the federated engine, see the

The red part is used to handle exceptions where no data is found. Create or replace trigger TIG_MONITOR_ALARM After insert on t_monitor_real_minuteFor each rowDeclare-- Standard valueStandvalue number;-- Alarm fact table idLiveid number;Begin----

I.Library Cache Lock     Library cacheHandle stores the lock and pin information. In addition, both the Library cache handle and child cursor have lock and pin. These are called library cache lock and library cache pin. Library cachelock/pin is

During daily use, hbase data in a cluster may need to be migrated to or copied to another cluster. At this time, many problems may occur. The following are some of my practices and handling methods in the process. Premise: the two hbase versions

Many systems only perform a flag when performing the delete operation, and do not perform operations that are as expensive as setting the disk to 0. The same is true for truncate. Only the segment header and I-node tables are changed. Truncate

Hot BackupSystemTablespace SQL> alter tablespace system beginbackup;  Tablespace altered.  SQL>! Cp/u01/tiger/oradata/orcl2/system01.dbf/bk  SQL> alter tablespace system end backup;  Tablespace altered Then make some transactions Destroy

(1) Multiple Oralce databases can be installed on one computer. (Instance), their SID cannot be the same (2) You can install multiple identical SID Oracle Database (Instance) (3) In the same network The global database name must not be the same

Oracle system cannot log on. My own problems are summarized as follows: First, access sqlpuls as SYS DBA Enable sqlpuls SQL-> enter the User name: sys as sysdba SQL-> password (old password ): Query the DBA user status after successful logon.

Q: What is Transfer? A: It is A solution to solve the native master-slave synchronization latency of MySQL. Transfer itself is a patch on the MySQL source code. It can be used as a server Load balancer or a third-party tool to synchronously send

Problems that may occur after Cacti is installed are related to the test: 1. snmp Test Snmpwalk-c public-v 2c localhost = "The result is normal. 2. Some mysql default installation may cause poller. php connection problems. The solution is to

On one server, you can use mysqld_multi to configure multiple Mysql instances to run. Assume that a MYSQL instance is running on the server. The data directory is/var/lib/mysql and the port is 3306. The SOCKET connection file used is located

Dual is a virtual table used to form the select syntax rule. Oracle ensures that there will always be only one record in dual. We can use it to do a lot of things, as shown below:1. view the current user. You can execute the following statement

Oracle 11g changes the database to archivelog mode. There are three ways to set automatic archiving in ORACLE 10G: 1. When you use DBCA to install a database, configure it to the automatic archiving mode. You can enable automatic archiving after