Oracle

6-1: Introduction to Subqueries6-2:SELECT * FROM Scott.empwhere sal= (select MIN (sal) from scott.emp);Example: Find out the company hires the earliest employees;Select min (hiredate) from Scott.empThe above query returns a single row of data, all

Select Initcap (' Guodongdong ') from dual; /returns a string and capitalizes the first letter of the string;Select Initcap (ename) from Scott.emp; /start all uppercase for ename in the Scott.emp table.Select Lower (ename) from scott.emp;/all

1. Locate the exp execution file from the Oracle installation directory and copy it to the specified directory:/home/fm/server/lib/oci/lib2. Copy the $oracle_home/rdbms directory below the ORACLE installation directory to the specified

The client asked which side of the data buffer was cached across Dblink, when combined with local and remote tables.The result of the test is that the local cache is locally cached and the remote table is cached at the remote end.# # #Testcase-0929-1

First, the basic usage:First press 11G beforeConn/as Sysdba;Create user test identifed by test;ORA-65096: The public user name or role name is not valid.Check the official document that "trying to create a generic user, you need to use C # #或者c #

--Create tableCREATE TABLE Prioffer_fund(Fundno VARCHAR2 (+) NOT NULL,Fundname VARCHAR2 (+) NOT NULL,Fundshortname VARCHAR2 (+) NOT NULL,Fundbelong VARCHAR2 (+) NOT NULL,Fundregist VARCHAR2 (+) NOT NULL,Builddate VARCHAR2 (10),Fundtypeo VARCHAR2 (40)

Exception information:Exception Information (Exception type: System.Data.OracleClient.OracleException) exception hint: Oracle Data execution exception, please contact the administrator to handle exception information: ORA - 01653 (in table space

1. Recoverable space allocation 2. Removable table space 3.Oracle Segment Shrinkage function 4.Oracle Database Resource Management Reference 1. Recoverable space allocation 1.1 understanding recoverable space allocationIn

Failure background:Operating system restart for the server, due to hardware problems, the server restarts after 128GB memory loss of half, causing the application process data processing slow. The Oracle software version is 10.2.0.5. In particular,

a transaction has four characteristics (ACID):atomicity (atomicity)Refers to the entire database transaction is an inseparable unit of work. The entire transaction succeeds only if all operations in the library are successful, and any SQL statement

Renaming a tableFor tables that already exist, you can also modify their names. There are two syntactic forms of renaming a table, oneis to use the ALTER TABLE statement with the following syntax:ALTER TABLE table_name RENAME to new_table_name;The

The first part of this paper is a plsql program, which realizes the salary increase for different positions, changes the data of the database. and commits the transaction; the second half combines the previous example with the data recovery in

Oracle Flashback Technologies-Flash back to the drop tableIn oracle10g, when a table is dropped, the table is not actually deleted, and the support is rename and placed in RecycleBin.#新建一个表y2, used to testSql> CREATE TABLE y2 as select * from

In the case of a duplicate installation, you first need to clear the existing Software installation record (only the red part is required for the first installation):Rm-fr/usr/local/bin/*oraenvRm-fr/usr/local/bin/dbhomeRm-fr/usr/tmp/.oraclerm-fr/tmp/

Java Project database migrated from Oracle to MySQL:MySQL connection URL in the role of Useunicode=true&characterencoding=utf-8: http://blog.csdn.net/afgasdg/article/details/6941712.Pom.xml File Dependency modified: http://mvnrepository.com/artifact/

First, the conceptA tablespace is a logical part of a database.Physically, the database data is stored in the data file;Logically, the database data is stored in a table space, and the tablespace consists of one or more data files.Second, the

SQL baseline information in an Oracle database that, when a performance problem occurs in the database, looks for changes in SQL by comparing the SQL baseline information when the business is unable to provide the appropriate business

First, what is the waterline (high water Mark)?All Oracle segments (segments, where, for ease of understanding, suggest segment as a synonym for a table) have a limit on the amount of data that can be accommodated in a paragraph, we call this cap

A single-line query is also called a single-line function that uses a function to manipulate data about a basic query:Oracle Basic Queries1Sql> Select lower (' Hello world ') Turn lowercase,2Upper (' Hello world ') to capitalize,3Initcap (' Hello

1. Use logical operation symbolsQuestion: Query for wages higher than 500 or job manager employees, but also to meet their initials in uppercase J?SELECT * from emp where (Sal > $ or job = ' MANAGER ') and ename like ' j% ';2. Use the ORDER BY