Oracle

  Queries SQL statements and forms a hyperlink for the second column Select id, concat ('', FILENAME ), ''), RANDOMFILENAME, FILESIZE "+" FROM T_FILEINFO   Oracle concat functions can connect only two strings at a time Select id, account,

  After years of experience with oracle, I found myself and some people around me have some bad development and operation methods in oracle usage, which can be used for reference. I. oracle programming: 1. The oracle code writing format is not

View which table is lockedSelect B. owner, B. object_name, a. session_id, a. locked_modeFrom v $ locked_object a, dba_objects BWhere B. object_id = a. object_idCheck which session is causedSelect B. username, B. sid, B. serial #, logon_timeFrom v $

Numeric FunctionsSQL code-- Both input and output are numbers.-- Abs (x) obtains the absolute value.Select abs (-1) from dual; -- 1 -- Ceil (x) returns the smallest integer greater than or equal to n.Select ceil (1.4), ceil (-2.5) from dual; -- 2,-2 

OAF provides two methods of Hot Keys.Mnemonic (Common) Accelerator Keys: generally used in the Prompt of the button.Numeric (Application-Specific) Accelerator Keys: generally used in menus or links. Mnemonic (Common) Accelerator KeysYou can add "&"

SQL> Select count (*) from v $ session where status = 'active ';COUNT (*)----------20SQL> Select count (*) from v $ session;COUNT (*)----------187SQL> show parameter processes;NAME TYPE

Complete oracle rman backup recovery example　Author: zhumy1. Create rman database as repository$ More createrman_db1.shSet echo onSpool makedb1.logCreate database rmanDatafile '/export/home/oracle/oradata/rman_data/system. dbf' size 50 m

1. List all departments with at least one employee.FirstSelect dname from deptWhere exists (Select * from emp where emp. deptno = dept. deptno);SecondSelect dname from dept where deptno in (select deptno from emp ); ThirdSelect dnameFrom deptWhere

I. Check the environment1.1 run the pre-check script and snapshot scriptWhether the database has data types not supported by OGG1.2 check the space for archiving logs on the production end.1.3 check the actual space occupied by the production

Both SQL server and mysql can set the primary key auto-increment, while the oracle primary key does not have the auto-increment attribute, which can be achieved through the following two methods:1. Create a sequence through a triggerCreate

Oracle Database lock and unlock view lock items: Table lock, row lock, etc., the following code SELECT /*+ rule */ s.username,decode(l.type,'TM','TABLE LOCK','TX','ROW LOCK',NULL)

Some errors encountered when installing Oracle 11.2.0.2.0 for RedHat5.4 _ 32bit -- analyze and solve some problems that have occurred recently when installing Oracle 11.2.0.2.0 for RedHat5.4 _ 32bit. 1. After the database software is installed, use

Oracle value functions 1. absolute value: abs () select abs (-2) value from dual; 2. take the entire function (large): ceil () select ceil (-2.001) value from dual; (-2) 3. take the entire function (small): floor () select floor (-2.001) value from

Back up data files on bare devices 1. using dd is the fastest method to accomplis h this. however, it isnecessary to know how many blocks to skip in the raw device (e.g ., on Tru64 uni x you must skip 64 KB) so that y ou do not overwriteinform ation

Tips for Oracle database query I. Cancel duplicate rows. For example, in the personnel management system, there is a basic employee information table. This table may contain fields such as department, position, employee name, and ID card number. If

Oracle cycle and process example: -- Create table t_test (test_id varchar2 (100), test_name varchar2 (100); -- Query select * from t_test; truncate table t_test; -- Declaration process -- insert test data with loop declare v_index number: = 1; begin

How to Improve the query statistics speed of ORACLE databases when developing large-scale oracle database systems, we have carried out some physical designs on the database in line with the principles of security and efficiency, in light of the

A Brief Introduction to Oracle Bad Block Processing Methods Oracle bad block processing involves two steps: 1. Check Bad blocks 2, fix the Bad blocks. You can use the DBV tool or the validate parameter in rman to detect the Bad blocks; 1) DBV tool:

Change of execution plan before and after index creation and comparison environment of soft and hardware resolution: OEL + Oracle 10.2.0.5 Rac answered a netizen's question on itpub today. RT: After I first executed an SQL statement, this SQL

Solve the problem of system slowdown after oracle is installedOracle Database is a resource-consuming software. The memory occupied by a single instance service must be at least MB Based on the memory allocated during installation. In addition,