Oracle

Oracle Database logs are called redo logs. All data changes are recorded in redo logs, which can be used to repair damaged databases. Large Databases use logs. The benefits of this design are the same. Redo logs are grouped. A database must have at

In oracle, only select statements in read-only transactions cannot have DML statements. All queries can only view the data before the transaction starts. Next I will introduce you to the Oracle read-only transaction test instance. We know that

ORA-12545 error is unable to connect to the target host IP address, or the object does not exist, the solution is to force the binding of the IP below we look at the two solutions. Oracle11GR2 RAC cannot connect to the database using scan IP, error

Three common methods for Oracle RAC Time synchronization are Network Time Protocol (NTP), rdate, and ntpdate. Let's take a look. 1. Use the ntpdate command 1. When the server can be connected to the Internet # Crontab-e Add a row: */1 ***** ntpdate 2

1.1 full database backup of Database DataNote: This operation requires you to start the database. Switch to the oracle user and create the backup directory on the OS side: Mkdir/oracle/backup Log on to the oracle database and create a backup

Cold backup is a physical backup of database files. It is usually performed after the database is shut down normally through a shutdown normal or shutdown immediate command. When the database is closed, all files used by the database can be backed

If you delete a non-existing TABLE in Oracle, such as "drop table notExistTable", the following message is displayed:ORA-00942: Table or view does not exist,If you run this statement using a program, an exception is reported. You need to delete the

I. Reasons Why empty tables cannot be exported1. By default, no segment is assigned to the empty table at Oracle11g. Therefore, when you use exp to export the Oracle11g database, the empty table is not exported. 2. After the

Many data blocks in the HWL are non-data, but the data blocks in the high-water line need to be scanned during full table scanning. That is to say, oracle has to do a lot of useless work! Therefore, oracle provides the shrink space fragment function.

The url address used to connect to the database is a bit different.Copy codeThe Code is as follows:Jdbc: oracle: thin: @ (DESCRIPTION =(LOAD_BALANCE = on)(ADDRESS_LIST =(ADDRESS = (PROTOCOL = TCP) (HOST = IP1) (PORT = 1521 ))(ADDRESS = (PROTOCOL =

Direct questionView Current Database Mode Connect to the database and enter the following command:Copy codeThe Code is as follows:SQL> archive log list; You can view the current database mode. If "Database Log mode is not archive mode", you need to

Brief introduction and application of TNS The complete definition of TNS in Oracle: the bottom layer of the transparence Network Substrate transparent Network. The Listener service is an important part of it, not all of which should not regard TNS

I. DescriptionThe oracle exp/imp command is used to export/import databases; The exp command is used to export data from a remote database server to a local machine to generate a dmp file; The imp command is used to import the dmp file of the local

This is a bit twisted solution, but works. basically you first need to convert LOB (in these example I refer to CLOB, BLOB is similar but you will probably not use varchar2) to multiple varchar2 (4000) on remote server-for example CLOB with size 8100

When tuning an Oracle database, each component has its own set of statistics. to look at the system as a whole, it is necessary to have a common scale for comparisons. for this reason, most Oracle Database advisories and reports describe statistics

DataDictionary and Dynamic Performance Views (data dictionary and Dynamic Performance attempt) This chapter describes the most important part of each database's read-only reference table (view), collectively referred to as the data dictionary. This

Cause of ORA-12560: TNS: protocol adapter error: 1. The listening service is not started. On the windows platform, perform the following operations: My computer-management-services and applications-services, open the service panel, and start the

In the actual optimization work, it is an important method to change the full table scan of the large tables in the execution plan into an index scan. When tuning a large table, it is inevitable to try to create an index, this is not very good. It

In Oracle, to improve SQL Execution efficiency, You need to reduce hard parsing to achieve shared cursor sharing. The most common method is to bind variables, however, in many cases, variable binding cannot be used at the initial stage due to

The following describes the Import and Export instances. You can simply import and export instances.Data export: 1. Export the database TEST completely, and the username system Password manager is exported to D: \ daochu. dmp. EnterExp