Oracle

User A in the database accesses user B's table t_department First, create dblinks in database a to link the two databases as follows: CREATE DATABASE LINKTestlink1ConnectAcsys// A user name of database BIdentified by "djzcq" // PasswordUsing 'B';

How to extract records by PAGEMethod 1: The rownum pseudo column of Oracle returns the row serial number of the query.For example, you can useSelect * From tablename where rownum However, to return 11th-20th records, try the following

1. Explain the differences between cold backup and hot backup and their respective advantagesAnswer: Hot Backup is applicable to databases in the archive mode. When the database is still in the working state, it is backed up. Cold backup refers to

I. Control Files The control file is a relatively small file (up to 64 MB ). The parameter file informs the instance of the control file location, and the control file informs the instance database and the online redo log file location. The

Cancel spfile parameter settings Alter system reset parameter SID = 'sid | *' Or alter system set parameter = value to the original value Create pfile using spfile Spfile is a binary file, pfile is a text file, you

Today, due to the working relationship, we need to design a backup solution for ORACLE. Because the database is large and it is not suitable for daily backups, we have designed a coverage backup of 7 files per week, the procedure is as follows:   1.

1. Definition of SCN SCN (System Change Number), That is, the system change number, is a very important data structure in the database. SCN is used to identify the version submitted by the database at a specific time. When a transaction is committed,

Bulk collect is used to reduce loop processing overhead. Bulk Collect is introduced in Oracle8i for the first time to improve Oracle query efficiency. This feature allows us to use batch query in PL/SQL, batch query can significantly improve query

I. analysis function overOracle provides analysis functions starting from 8.1.6. The analysis function is used to calculate a group-based aggregate value. Different from the aggregate function, it returns multiple rows for each group, the aggregate

Recently, oracle materialized views have been updated based on the project business needs. You can search for information on this topic on the Internet to facilitate improvement. The content is as follows: Materialized View is a special physical

Query/Check Privileges in Oracle Database §-- Determine the role privileges Select*FromRole_tab_privs; -- The object privileges granted to roles in data dictionary views. Select*FromRole_role_privs; -- Containing the role granted to another role.

ORacleMethods for generating random numbers Selectdbms_random.random from dual;   Select abs (mod (dbms_random.random, 100) from dual; -- generate a random number between 0 and 100.   Selecttrunc (100 + 900 * dbms_random.value) from dual; -- 100

      Oracle paging query statements can be applied in the format given in this article.   Paging Query format:    View Code SELECT * FROM ( SELECT A.*, ROWNUM RN FROM (SELECT * FROM TABLE_NAME) A WHERE ROWNUM = 21     SELECT * FROM TABLE_NAME

When starting TNSListener, Oracle Servlet Engine of oracle9i occupies port 8080, causing inconvenience to other programs that need to use port 8080. The following are two ways to solve the problem of using port 8080. Solution:After installation,

1. Establish package specifications Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->Create or replace package QX_GDJTJ is -- Author: liuwei-- Created: 10:20:05-- Purpose: Count master device

1. DMP file (imp/EXP) The DMP file is backward compatible, indicating that the new version can read the old version of DMP. For DMP file rules: the Export version of the DMP file must be smaller than or equal to the Import version of the DMP file.

1. parameter file How to view parameters Show parameter name Select * from v $ parameter Server parameter file Spfile is an important change in ORAcle. With PFILE, it can eliminate two serious problems in traditional parameter

1. Trace file) Provides detailed debugging information. When a server fails, a trace file containing a large amount of diagnostic information is generated. Enable tracking SQL _TRACE = TRUE Measure oracle V $ view, such as v $ waitstat and

A few days ago, I used oracle to add and modify tables. The trigger content is to generate local text files every day, and the file content is to add and modify table data, to automatically upload data to the server for synchronization. First, you

-- Create tablespace test_tablespace logging datafile 'e: \ ORACLETABLESPACE \ test_tablespace.dbf' SIZE 32 m autoextend on next 32 m maxsize 2048 m extent management local; -- Create temporary tablespace test_temptablespace tempfile e: \