Oracle

1. subqueries nest another SQL statement in one SQL statement into subqueries. When a problem cannot be solved through one clause, subqueries can be considered. A subquery that appears in the FROM clause of the SELECT statement is called "embedded

Dblink mode: 1 Create public database link xxxx connect to xxxx identified by xxxxusing 'xxxx'; -- select 'drop table' | trim (xxxx) | '; 'From dt_tabinfo where dw_sysid = '000000' -- 2 select 'create synonym' | trim (dw_tabid) | 'for TOTALPLANT. '|

Oracle Startup Process Analysis:Oracle generally has several statuses: shutdown, nomount, mount, and open. shutdown to nomount: oracle loads the initialization file to the default directory based on the sid in the environment variable, there are two

Tips on Oracle optimization: Methods for Improving ORACLE performance (indexing SQL statements as much as possible) SQLOracle script I. question raised at the early stage of application system development, due to the small amount of data in the

Linux after the installation of oracle restart can not log on to the database ORA-01034: ORACLE not available solution yesterday installed the database, after the installation can be used, start today can not be used, prompt ORACLE not available,

Oracle-Example of modifying the field type: l_amount_temp is a temporary field, and L_AMOUNT is a field to be modified. SQL code alter table alter add l_amount_temp int; www.2cto.com alter table modify L_AMOUNT NULL; update into set l_amount_temp =

1. log on to my Objecttools --> Browser Filter by default. In the displayed window, select defalut 2 in my object. log on to the password and automatically save tools --> Preferences --> Logon History check store with password www.2cto.com 3. press

Fully uninstall Oracle 9I software environment in Windows XP: 1 Windows XP + oracle 9i2 Oracle installation path: E:/oracle start uninstall: 1 start --> set --> control panel --> management tools --> services --> stop all oracle Services 2 start -->

The oracle Net Manager Service name cannot be configured. Today, when you configure the oracle Net Manager Service name, the service name configured previously cannot be displayed, then, clicking the green Add button does not respond, because I

After a piece of SQL code is written, you can view the SQL Execution Plan To preliminarily predict the performance of the SQL statement at run time, especially when the efficiency of an SQL statement is found to be poor, we can view the execution

Dba_users Database user Information dba_segments table segment information dba_extents data zone starting with dba _, user _, v $ _, all _, session _, and index _ in oracle information dba_objects database object information dba_tablespaces database

Analysis of oracle tree SQL query: select typecode, lpad ('', 4 * level-1) | typename from ajtype start with p_code is null connect by prior typecode = p_code; Result: 1 + city appearance and sanitation 15 + lighting management 151 + refusal to

/* Total number of patients with high disease in the administrative village of the Production and Marketing institution the number of high-severity patients managed this month (one service per year) the number of high-severity patients managed this

Related Links: Exploring the RMAN_01 concept of ORACLE http://www.bkjia.com/database/201205/132243.html Explore the basic use of RMAN_02 in ORACLE http://www.bkjia.com/database/201205/132329.html As mentioned earlier, backups are classified into

During the past two weeks, I have been busy with the migration of databases. When I did not do it, I felt it was very easy, but I was dumpfounded when I did it. In this tangle, let's talk about the problem:1. Database Table Structure Problem:

Combined Query, as its name implies, combines two or more tables to perform complex queries. The combined query is a bit similar to the high mathematics: Set. It is further divided into: full set, subset, union, and intersection. Preview the tables

Use cursor cur_2 is select. cust_name from ea_cust.cust_info a; cust_id varchar2 (100); begin open cur_2; loop fetch cur_2 into cust_id; exit when cur_2 % notfound; NULL; end loop; close cur_2; end; -- takes 48 seconds 2. Implicit cursor declare

1. Logon: 1. sqlplus enter the user password as prompted, but there is no place to enter the database connection string. You need to set ORACLE_SID in advance. 2. sqlplus user/pass @ db log on directly. The disadvantage is that the password may be

ORACLE incomplete backup series uses rman-based Incomplete recovery SQL> select * from test; a ----- 123456sql> hostramn target/rman> run {allocate channel c1 type disk; bakup full tag 'dbful' format 'd: \ backup \ full _ % u _ % s _ % P'

How to view the permissions of oracle users the types of ORACLE Data Dictionary views are: USER, ALL, and DBA.USER _ *: Information about objects owned by users, that is, information about objects created by users ALL _ *: Information about objects