Oracle

This problem has plagued me before, and both of them are suffixed with. DBF. I remember that I posted a post on the Forum, but no one answered the question for several days. I ended the post. Today, I saw the difference between the two in a book,

System Recovery segment Used only for changes to objects in the system tablespace. It is created in the system tablespace when the database is created. The system recovery segment can exist and work in the automatic mode or in the manual mode.  

A while ago, I saw a specific process about delete operations. Today I accidentally saw another update operation process, which is interesting. Let's go and learn it! ========================================================== =======================

Note:1. This document uses oracle9.2 as the testing and analysis version.2. The Oracle object names mentioned in this article include the table name, view name, field name, and function name in Oracle. The following is an example of using different

13. Calculate the number of recordsIn contrast, count (*) is slightly faster than count (1). Of course, if you can search by index, the index column count is still the fastest. For example, count (empno)According to the author's suggestion: In the

In Oracle, you can use the instr function to determine whether a string contains specified characters. Its syntax is:Instr (sourcestring, deststring, start, appearposition ).Among them, sourcestring indicates the source string; deststring indicates

4. Select the most efficient table name sequence (only valid in the rule-based Optimizer)The Oracle parser processes the table names in the from clause in the order from right to left. ThereforeThe base table driving table written in the from clause

1. userevn () Returns information about the current user environment. The opt can be:Entryid, sessionid, terminal, isdba, lable, language, client_info, Lang, vsize   1. isdba check whether the current user is a DBA. If yes, true is returned.SQL>

It is true that the same content is different for the second time. Some of them were not carefully understood during the first time, some of them may be skipped in a rush for the first time. Of course, some of them may be forgotten after they are

SQL> select * from users; NAME value ID-------------------T1 A 1T2 B 2T3 C 3T4 D 4   -- Implement the combination of values in the value column   SQL> select Replace (sys_connect_by_path (value, '#'), '#') combo2 from users3 where level = 24 connect

7. Object type inheritance   Object Type implementation allows us to create a base type, or a parent type. attributes or methods of this type can be inherited by another object type. Then you can create a child type, or the child type, to directly

Ii. Define and use records and object types as parameters When used as a formal parameter, there are many similarities between the record type and the object type. Before using them as parameters in the form of a cursor, function, or procedure, you

SQL> select dbms_metadata.get_ddl ('Procedure ', 'pro2', 'Scott') text from dual; text -------------------------------------- Create or replace procedure "Scott ". "P RO2" is begin dbms_output.put_line ('wangpeng up'); end; SQL> select

Extent_management_clause Theextent_management_clause Lets you specify how the extents of the tablespace will be managed. Note: After you have specified extent management with this clause, you can change extent management only by migrating the

The processes in an Oracle system can be categorized into two major groups:■ User processes run the application or Oracle tool code.■ Oracle processes run the Oracle database server code. They include server processes and background

Oracle servers generally include the following three installation methods: Host-Based Mode: In this configuration, you can directly log on to the Oracle database on the computer where the database is installed. Client-server (two-layer model):

I have previously reproduced an article on backup and recovery of controlfile. The address is as follows: Http://blog.csdn.net/wh62592855/archive/2009/11/20/4844506.aspx   Control File Content Today, I suddenly wondered what information is contained

I have previously published an article on how to move data files. For more information, see Http://blog.csdn.net/wh62592855/archive/2009/11/20/4843764.aspx However, we only provided one example at the time. Today we see another method in the book.

Today, I see a section on the storage clause priority. To tell the truth, when creating an object, the storage clause is hardly specified. Generally, the default value is used. Well, it may be because you are too lazy. If you see it today, remember

Step 1: Search for the refhost. xml file in the decompressed Oracle folder. Two matching files are displayed in the search result, both of which need to be modified. When the file is opened, it contains system instructions such as... 5.0 6.0.Note: