Oracle

Lunatic sorting 1. Notes for deleting a tableWhen deleting all data in a table, the truncate table name must be used. Because when the drop table or delete * from table name is used, the occupied space of the table in the tablespace is not

In Oracle, sys_guid () can be used to generate a guid, which is equivalent to newid () in MSSQL (). In Oracle9i and Oracle 10g, sys_guid generates 32-bit data, for example, 234e45f0077881aae0430aa301_1aa. However, the guid format in Oracle is

1. To_date format (take time: 13:45:25 as an example)Year:YY two digits two-year display value: 07YYY three digits: 007Yyyy four digit 2.Select to_char (to_date (222, 'J'), 'jsp ') from dualDisplay two hundred twenty-two 3. Check the day of the

To use ORACLE data provider for. Net (ODP. Net ), You must first install ODP. Net or odac (Oracle Data Access Components) (Odac contains the ODP. NET Component) It is best to install ODT. net. In this way, Oracle Applications will be developed

1. Export tool exp 1. It is the next executable file in the operating system.Storage directory/ORACLE_HOME/bin The exp export tool compresses data backup in the database into a binary system file, which can be migrated between different

Database optimization greatly improves Oracle PerformanceSeveral Simple Steps greatly improve Oracle performance-I optimized the database three axes.Database optimization is an eternal topic. Senior Oracle optimizer usually asks the person who

Use ultraedit32 to open the exported DMP file. The file content is displayed in hexadecimal notation. The second and third bytes of data record the character set of this file. For example: 03 54 Convert it to a 10-digit system with a value of 8

Since last week, a problem occurred in the Oracle database on the server. In less than half a day, the maxsession (150) problem will be reported. It must be because the maximum number of database sessions has exceeded.Because the server runs a file

As we all know, in 32-bit operating systems such as Win2k, the memory that the operating system can manage is 4 GB (Power (2, 32) = 4 GB), and the total memory used by Oracle is limited to 2 GB. Currently, most information systems can provide

FAQs about Oracle Metalink Gototop Note: This article is from Oracle and is for reference only! 1. What is Metalink?2. How to register a Metalink account?3. How can I customize my title?4. How to enter Metalink?5. How to add another customer

Problem: After the oracleorahome92tnslistener service is started, it will be automatically disabled, leading to database unavailability.Cause: the host name is changed after oracle is installed.Solution: Modify the D: \ oracle \ ora92 \ Network \

From: http://hi.baidu.com/andyloolu/blog/item/a64f0ed12cc10738960a165a.html In Oracle, you can define package variables. Many people are not very clear about the use of package variables. First, let's look at the following example: Create or

Conditional loops can be implemented in two ways.1. For variable in start value... end value loop end loop;2. While condition loop end loop; Loop usage:I. X: = 100;LoopX: = x + 10;If X> 1000 thenExit;End if end loop;Y: = X;Ii. X: = 100;LoopX: = x +

Oracle's imp/exp component is a common tool. One of its operational principles is Backward compatibility . The following are the usage rules and related tests summarized as follows: Rule 1: earlier versions of exp/IMP can be connected to database

The problem is, Oracle had to be installed some days ago due to learning needs, However, the downloaded Oracle 9i R1 cannot be installed in my win7 environment, Since I cannot bear win7 (I don't want to switch back to XP), I installed Oracle 10

  1. Flashback drop    Currently, Oracle10g provides the new flashback drop feature to accelerate the recovery of user error operations.    The flashback drop function allows you to restore a dropped object from the current database. When

1. Avoid Dynamic Allocation DefectsCreate a local table space;Set the segment size properly;Monitor the segment to be extended:Select owner, table_name, blocks, empty_blocks from dba_tables where empty_blocks/(blocks + empty_blocks) 2. high water

Common Oracle Data Dictionary tables view the default tablespace of the current user SQL> select username, default_tablespace from user_users; View the role of the current userSQL> select * From user_role_privs; View the system and table-level

Oracle 11g allows marking an index as invisible. OracleSame as maintaining other indexesInvisible IndexBut the default invisible index cannot be used by the optimizer, unless explicitly setOptimizer_use_invisible_indexes= True (you can alter

Before developing a database system, who knows a lot about the Oracle system, especially its features? It seems very rare. For Beginners, this is even more impossible; with a simple understanding of the SQL writing method, we started database