Oracle Database Developer

Based on Oracle Web site: Oracle Database 10g Express Edition (Oracle Database XE) is an entry-level, small-footprint database based on the Oracle Database 10g Release 2 code base that's free to develop, deploy, and distribute; fast to download; and simple to administer. Oracle Database XE is a great starter database for:

* Developers working on PHP, Java, .NET, and Open Source applications

* DBAs who need a free, starter database for training and deployment

* Independent Software Vendors (ISVs) and hardware vendors who want a starter database to distribute free of charge

* Educational institutions and students who need a free database for their curriculum

Oracle Database XE is free for runtime usage with the following limitations:

* Supports up to 4GB of user data (in addition to Oracle system data)

* Single instance only of Oracle Database XE on any server

* May be installed on a multiple CPU server, but only executes on one processor in any server

* May be installed on a server with any amount of memory, but will only use up to 1GB RAM of available memory

Oracle Database 10g Express Edition is available for two types of operating Systems:

* Linux x86 - Debian, Mandriva, Novell, Red Hat and Ubuntu

* Microsoft Windows

To install 10g universal edition, double click, OracleXEUniv.exe, the install wizard starts. It will guide you to finish the installation process. You should take notes about:

* The SYSTEM password you selecte: globalguideline.

* Database server port: 1521.

* Database HTTP port: 8080.

* MS Transaction Server port: 2030.

* The directory where 10g XE is installed: oraclexe

* Hard disk space taken: 1655MB.

If you want to check your fresh installation of 10g Express Edition without using any special client programs, you can use a Web browser with this address, http://localhost:8080/apex/.

You will see the login page. Enter SYSTEM as the user name, and the password (globalguideline), you selected during the installation to log into the server.

Visit different areas on your 10g XE server home page to make sure your server is running OK.

You can also get to your 10g XE server home page by going through the start menu. Select All Programs, then Oracle Database 10g Express Edition, and then Go To Database Home Page.

If you want to shutdown your 10g Express Edition server, go to the Services manager in the control panel. You will a service called OracleServiceXE, which represents your 10g Express Edition server.

Select OracleServiceXE, and use the right mouse click to stop this service. This will shutdown your 10g Express Edition server.

You can also shutdown your 10g XE server through the start menu. Select All Programs, then Oracle Database 10g Express Edition, and then Stop Database.

Go to the Start menu, select All Programs, Oracle Database 10g Express Edition, and Start Database.

Your 10g XE Server is using about 180MB of memory even there is no users on the server. The server memory usage is displayed on your server home page, if you log in as SYSTEM.

You can start your 10g XE server from command line by:

* Open a command line window.

* Change directory to oraclexeapporacleproduct10.2.0serverBIN.

* Run StartDB.bat.

The batch file StartDB.bat contains:

net start OracleXETNSListener

net start OracleServiceXE

@oradim -startup -sid XE -starttype inst > nul 2>&1

You can shutdown your 10g XE server from command line by:

* Open a command line window.

* Change directory to oraclexeapporacleproduct10.2.0serverBIN.

* Run StopDB.bat.

The batch file StopDB.bat contains:

net stop OracleServiceXE

Your 10g XE server comes with a sample database user account called HR. But this account is locked. You must unlock it before you can use it:

* Log into the server home page as SYSTEM.

* Click the Administration icon, and then click Database Users.

* Click the HR schema icon to display the user information for HR.

* Enter a new password (hr) for HR, and change the status to Unlocked.

* Click Alter User to save the changes.

Now user account HR is ready to use.

Your 10g XE server has a default setting for System Global Area (SGA) of 140MB. The SGA size can be changed to a new value depending on how many concurrent sessions connecting to your server. If you are running this server just for yourself to improve your DBA skill, you should change the SGA size to 32MB by:

* Log into the server home page as SYSTEM.

* Go to Administration, then Memory.

* Click Configure SGA.

* Enter the new memory size: 32

* Click Apply Changes to save the changes.

* Re-start your server.

Your 10g XE server has a default setting for Program Global Area (PGA) of 40MB. The PGA size can be changed to a new value depending on how much data a single session should be allocated. If you think your session will be short with a small amount of data, you should change the PGA size to 16MB by:

* Log into the server home page as SYSTEM.

* Go to Administration, then Memory.

* Click Configure PGA.

* Enter the new memory size: 16

* Click Apply Changes to save the changes.

* Re-start your server.

Let's you made a mistake and changed to SGA to 16MB from the SYSTEM admin home page. When you run the batch file StartDB.bat, it will return a message saying server stated. However, if you try to connect to your server home page: http://localhost:8080/apex/, you will get no response. Why? Your server is running, but the default instance XE was not started.

If you go the Control Panel and Services, you will see service OracleServiceXE is listed not in the running status.

If you logged in to the server as a SYSDBA, you start the default instance with the "startup" command. Here is how to start the default instance in SQL*Plus in SYSDBA mode:

>.insqlplus

Enter user-name: SYSTEM/globalguideline AS SYSDBA

Connected to an idle instance

SQL> show instance

instance "local"

SQL> startup

ORA-00821: Specified value of sga_target 16M is too small,

needs to be at least 20M

Now the server is telling you more details about the memory problem on your default instance: your SGA setting of 16MB is too small. It must be increased to at least 20MB.

Settings for each instance are stored in a file called Server Parameter File (SPFile). Oracle supports two types of parameter files, Text type, and Binary type. parameter files should be located in $ORACLE_HOMEdatabase directory. A parameter file should be named like "init$SID.ora", where $SID is the instance name.